Early Externalizing Behavior Problems: Toddlers and ...

Early Externalizing Behavior Problems: Toddlers and Preschoolers at Risk for Later Maladjustment

Susan B. Campbell, Daniel S. Shaw, and Miles Gilliom Department of Psychology University of Pittsburgh

Running head: Early Externalizing Behavior Problems

Early Externalizing Behavior Problems

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Early Externalizing Behavior Problems: Toddlers and Preschoolers at Risk for Later Maladjustment The early emergence and developmental implications of externalizing behavior problems in toddlers and preschoolers are discussed with an emphasis on which young children are truly at risk for continuing problems. The extant literature is reviewed with a focus on the stability of early externalizing behavior and the diverse pathways that young children, primarily boys, with early-emerging problems may follow. Findings from a number of studies, both epidemiological and high risk, suggest that the small subgroup of boys with multiple risk factors that include especially high levels of early hyperactivity and aggression, and high levels of negative parenting and family stress are most likely to evidence continuing problems at school entry. Sociodemographic and neighborhood influences are also discussed, as are implications for future research and policy.

key words: externalizing problems, early onset, developmental course, multiple risk.


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Early Externalizing Behavior Problems: Toddlers and Preschoolers at Risk for Later Maladjustment In this paper, we will discuss the early emergence and developmental implications of externalizing behaviors in toddlers and preschoolers. We will begin with a brief historical overview. Next, issues central to the field of developmental psychopathology, continuity-discontinuity and risk factor models, will be addressed as they relate specifically to the emergence of externalizing problems in young children. These issues will be illustrated with findings from two longitudinal studies of children at risk for psychopathology. Finally, we will discuss directions for research in the 21st century. Historical Overview Theoretical and Research Advances. Trends in developmental psychology and in child psychopathology have converged over the last 30 years to lead to the conceptually integrative field of developmental psychopathology (Cicchetti & Cohen, 1995; Cicchetti & Richters, 1993; Sroufe & Rutter, 1984). These theoretical influences have been crucial for the study of adjustment and maladjustment in young children and for understanding the degree to which early problem behaviors predict later functioning. Despite the growing interest in the developmental antecedents of externalizing problems, however, child psychopathology research and practice have focused almost exclusively on school-age children until relatively recently. Externalizing symptoms in early childhood such as marked noncompliance, aggression toward peers, high activity level, and poor regulation of impulses were considered typical behaviors of toddlerhood and the preschool period, with few long-term implications for later adjustment (Campbell, 1990). Parents who complained about these problems to professionals were often told that their child would outgrow the problem or that he was "just being a boy." Of course, in many instances, this advice from pediatricians and others was correct. At the same time, however, some proportion of very aggressive, defiant, and overactive toddlers and preschool children will continue to have problems at school age (e.g., Campbell, Pierce, Moore, Marakovitz, & Newby, 1996; Shaw,


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Winslow, & Flanagan, 1999), and for some, these problems may even continue into adulthood (Moffitt, 1993a). Limited concern about the early manifestations of problem behavior reflected, among other things, conceptual and measurement gaps, the relative lack of attention to developmental issues in child psychopathology, and the focus on children who were clinically-referred, who also were usually already in school (Campbell, 1990). Several trends in the field over the last 30 years have led to a renewed interest in younger children who may be at risk for psychopathology or may be showing early signs of problem behavior that is unlikely to come to clinical attention before school entry. The interest in early infant temperament, and the possibility that intense infant irritability and unconsolability might be an early sign of incipient behavior problems (Thomas, Chess, & Birch, 1968), was one major influence. The publication of Thomas et al.'s seminal book on temperament and behavior problems reflected the swing away from psychoanalytic formulations of problem behavior and focused attention instead on the "goodness-of -fit" between parents and children. Sameroff and Chandler’s (1975) work on transactional systems was also influential in expanding on Thomas’ and Chess’ framework, emphasizing the need to study parent-infant interactions over time to fully understand the infant's ability to regulate negative emotion. Undoubtedly, too, the emergence of attachment theory as a major influence on conceptualizations of early infant development and parent-infant relationships (Ainsworth, Blehar, Waters, & Wall, 1978; Bowlby, 1969; Sroufe, 1983) highlighted parental responsiveness and relationship quality as powerful influences on early development. These dual emphases on infant temperament and quality of attachment underscored the renewed interest in individual differences in development. The insights into the dynamics of parent-child interaction that emerged from social learning theory also focused attention on individual differences in parenting (e.g., Dumas & Wahler, 1985; Patterson, 1982). These in turn led to the development of more complex conceptual models that include transactional processes and broad ecological influences (Bronfenbrenner, 1986; Sameroff, 1995)


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highlighting multiple interacting factors that may lead one difficult infant to become an engaging toddler, whereas another difficult infant becomes increasingly defiant, angry, and hard to control. In the child psychopathology area, the work of Richman, Stevenson, and Graham (1982) revealed that as many as 60% of three-year-olds with extreme scores on measures of externalizing behavior would continue to have difficulties in middle childhood. Other researchers were also becoming interested in the manifestations of hyperactivity and related problems in very young children, partly influenced by the emerging focus on individual differences in parent-child relationships in developmental psychology and by an interest in child characteristics such as infant temperament that might predict which young children with early difficulties would continue to show adjustment problems (e.g., Campbell, 1976). These trends, paired with clinical experience, led Weiss and colleagues to undertake an early study of hyperactive preschoolers (Schleifer, Weiss, Cohen, Elman, Cvejic, & Kruger, 1975) who were then followed up at age 6. Problems continued when early symptoms were severe and evident across settings (Campbell, Schleifer, Weiss, & Perlman, 1977). Thus, the data from this and other studies indicated that problems could be identified early and that in many instances they were not just transient developmental disturbances, but indeed early precursors of the externalizing problems evident in school-age children: hyperactivity/attention deficit disorder, oppositional behavior, and conduct problems (Campbell, Szumowski, Ewing, Gluck, & Breaux, 1982; Carlson, Jacobvitz, & Sroufe, 1995; Crowther, Bond, & Rolf, 1981). More recent studies with even younger children, focusing on aggression, demonstrate that both observed aggression and parental reports of externalizing behaviors are relatively stable from toddlerhood to age 5 and beyond (e.g., Cummings, Iannotti, & Zahn-Waxler, 1989; Keenan & Shaw, 1994; Pierce et al., 1999). Moreover, when these symptoms reach the level of a diagnosable disorder in school-age children and adolescents, they are relatively resistant to treatment (Hinshaw, 1994; Kazdin, 1993), leading to an increased emphasis on the early prevention of externalizing problems (Conduct Problems Prevention Research Group, 1992). We now turn to a brief discussion of these behaviors and their associated disorders.


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Attention Deficit Hyperactivity Disorder (ADHD). ADHD is among the most common disorders of childhood, and it has been the subject of research for nearly a century (Barkley, 1998). ADHD was first described in 1902 by a British physician as a lapse in "volitional control" (Still, 1902). There is now general agreement that the core features of inattention, impulsivity, and hyperactivity define ADHD. However, changing conceptions have led to somewhat different definitions and emphases. In the 1950's and 60's, emphasis was placed on the activity component (Laufer & Denhoff, 1957); by the 1970's, the focus had shifted to attentional problems (Douglas, 1983; Douglas & Peters, 1978); most recently, more weight has been placed on the poor impulse control (lack of inhibition) that characterizes this disorder, reflecting a return to questions about the regulation of affect, behavior, and cognition, as well as a renewed emphasis on underlying biological factors (Barkley, 1997). In the DSM-IV (American Psychiatric Association, 1994), ADHD is defined by nine symptoms of inattention; six of hyperactivity; and three of impulsivity. In addition, children with ADHD often have associated problems that include aggression, oppositional behavior, peer difficulties, and learning problems. Indeed, most children with a diagnosis of ADHD also meet criteria for another DSM diagnosis, usually Oppositional Defiant Disorder or Conduct Disorder (Barkley, 1997; Jensen, Martin, & Cantwell, 1997). Although early research on hyperactive children failed to take co-occurring disorders into account, follow-up studies indicate that ADHD children with co-occurring conduct problems have more severe and persistent problems in adolescence and adulthood (Barkley, Fischer, Edelbrock, & Smallish, 1990; Weiss & Hechtman, 1993). Thus, the combination of these disorders is associated with poorer long-term adjustment. Conduct Problems. The term conduct problems encompasses a range of aggressive, defiant, and antisocial behaviors that have as their hallmark the violation of the rights of others and major social norms (American Psychiatric Association, 1980, 1994). These run the gamut from annoying interpersonal behaviors such as being argumentative, defiant, and stubborn, to physical violence (fighting, assault, cruelty to animals), to secretive antisocial acts such as truancy, drug and alcohol use/abuse,


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vandalism, and theft. Thus, it is evident that these behaviors vary widely in terms of severity and the degree of damage done to society and the rights of others, and they include those that are clearly illegal (assault, illicit drug use, theft) as well as those that merely reflect parent-child or peer conflict (noncompliance with adults, fighting with or bullying peers). Conduct problems also fall under several rubrics and social systems, and this also complicates classification and definition. Delinquency, for example, is primarily a legal term that refers to children who have been arrested for antisocial behavior. However, the term delinquency is also used as a clinical descriptive label for these behaviors (Achenbach, 1991). The DSM-IV includes two diagnoses that capture these behaviors, Oppositional Defiant Disorder (ODD) and Conduct Disorder (CD). Because terms such as conduct disorder and delinquency are sometimes used interchangeably, it should be noted that many delinquent children and adolescents may not meet diagnostic criteria for CD; conversely, many, if not most, children with a diagnosis of CD have not been arrested, so they would not be considered delinquent in the legal sense of the term. ODD, which is seen by some as a developmental precursor of CD (Lahey et al., 1992; Lahey, Waldman, & McBurnett, 1999), reflects negative, irritable, and noncompliant behavior, and as noted above, it often co-occurs with ADHD in young children. Historically, conduct problems have been studied primarily in school-age children and adolescents, although the recent upsurge of interest in individual differences in aggression in very young children partly reflects an attempt to understand the early manifestations of aggression and related behaviors prior to the emergence of full-blown and stable problems (e.g., Keenan & Shaw, 1994; Shaw et al., 1996). Co-Morbidity. The co-occurrence of ADHD and ODD or CD has become of central importance to the field recently. This partly reflects the well-documented overlap between these disorders (e.g., Hinshaw, Lahey, & Hart, 1993; Offord et al., 1989), as well as the fact that ADHD children with co-occurring aggression or ODD tend to have more serious problems when followed up in adolescence (Barkley et al., 1990) and adulthood (Weiss & Hechtman, 1993). Researchers in the area of conduct disorder have likewise posited that poor impulse control and overactivity may be developmental


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precursors of more severe and chronic conduct disorders (Loeber, 1988) and that the cognitive deficits associated with ADHD (inattention, poor organization and planning) may likewise be early markers of persistent conduct problems (Moffitt, 1993b). Others have suggested that ADHD in tandem with conduct problems may constitute a distinct disorder (Jensen et al., 1997) with a unique set of causes and correlates, and a potentially poor developmental course. Thus, it is logical to examine children with early signs of both hyperactivity-impulsivity and aggression-noncompliance and to follow them prospectively to discover which children will go on to evidence persistent problems reflecting symptoms of these co-morbid disorders. Developmental Issues and Pathways Overactivity, poor regulation of impulses, noncompliance, and aggression are common complaints of parents of young children (e.g., Koot, Van Den Oord, Verhulst, & Boomsma, 1997; Richman et al., 1982), as well as defining features of ADHD, ODD, and CD. An interest in identifying very young children who are at risk for externalizing problems, then, poses the challenge of differentiating age-related, relatively normative, and transient levels of these behaviors from more serious early-emerging problems (Campbell, 1990, 1995). Campbell (1990) proposed that clinically significant problems are most likely to be evident when a young child shows a constellation of co-occurring problems that are relatively frequent and severe, that cut across domains of functioning (e.g., social, cognitive), are evident across situations (e.g., home and child care), and are expressed with different people (parents, peers, caregivers). Moreover, problems are most likely to persist in the context of family dysfunction and stress (e.g., Ackerman, Kogos, Youngstrom, Schoff, & Izard, 1999; Campbell, 1997; Greenberg, Lengua, Coie, & Pinderhughes, 1999), presumably because stressed parents are more likely to engage in harsh or inconsistent parenting (e.g., Campbell et al., 1996; Harnish, Dodge, & Valente, 1995; McLoyd, 1998; Patterson, Debaryshe, & Ramsey, 1989), which in turn exacerbates early parent-child struggles over autonomy and control. Thus, in some social contexts, parents' behavior may fuel noncompliance, aggression, and poor regulation of negative emotion, rather than provide toddlers


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adaptive models of regulated and prosocial functioning (Rubin, Hastings, Chen, Stewart, & McNichol, 1998). From a transactional and ecological perspective (Sameroff, 1995), then, early parent-child conflict, beginning in toddlerhood (e.g., Belsky, Woodworth, & Crnic, 1996; Shaw & Bell, 1993), may set the stage for more prolonged coercive exchanges that become an entrenched feature of the parent-child relationship (Patterson & Yoerger, 1997; Snyder, 1991). Typical, but annoying, behaviors in toddlers such as outright defiance to parental requests (no!), toy-taking (it's mine!) and other signs of aggression toward siblings or peers, and difficulty controlling anger (e.g., tantrums) most often reflect attempts to establish autonomy, test limits, master environmental constraints, and practice social skills (e.g., Campbell, 1990; Crockenberg & Litman, 1990; Kopp, 1989; Shantz, 1987). These very same behaviors, however, may become symptoms of emerging disorder if they continue unabated past the time that they are seen as age-appropriate expressions of frustration or autonomy-seeking, or if they worsen over time, and interfere with the development of more age-appropriate social and communicative skills such as negotiating, sharing, and playing cooperatively. Why do some toddlers develop from whiny and defiant two-year olds to more cooperative and positive three-year-olds, whereas others become more difficult with development? Do these early behaviors have implications for understanding more serious long-term problems reflected in clinical diagnoses and/or more general signs of maladjustment in middle childhood, adolescence, or adulthood? These are important questions for the developmental psychopathology arena. Whereas historically, as already noted, these early behaviors were dismissed as having little relevance to understanding child psychopathology, more recently, as noted by Bennett, Lipman, Racine, and Offord (1998), there has been a tendency to overgeneralize and to suggest that difficult behavior in early childhood is frequently a precursor of more serious antisocial behavior in adolescence and adulthood. These views reflect extremes in the discontinuity-continuity debate. Clearly, both discontinuity, reflected in poor predictability from early to later behavior, and continuity, reflected in good predictability, are in evidence, but for whom?


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Consistent with the dual emphasis on temperament and the parent-child relationship discussed earlier, attempts to answer the question of which children with early signs of problem behavior will go on to show more serious problems later have focused on within child factors (e.g., Caspi, Henry, McGee, Moffitt, & Silva, 1995; Lahey, Waldman, & McBurnett, 1999; Moffitt, Caspi, Dickson, Silva, & Stanton ,1996) and on parent-child relationship factors (Carlson et al., 1995; Greenberg, Speltz, & DeKlyen, 1993; Patterson & Yoerger, 1997; Speltz, DeKlyen, & Greenberg, 1999) as major predictors of problem stability. Thus, for example, Moffitt and colleagues have argued that explosive and undercontrolled behavior identified in early childhood is one precursor of antisocial behavior that persists. Lahey and colleagues have suggested that a particular constellation of personality characteristics that includes oppositionality and negative mood in infancy, low fearfulness, and lack of empathy describe children with propensities to become antisocial. These formulations are consistent with trait theories as well as the idea that early temperamental difficultness may be one precursor of externalizing problems. However, these conceptualizations are more specific in that they focus on high levels of negative affect that characterize some children who then do not learn to regulate their mood or emotional expression effectively. Moreover, a lack of empathy may make some children more difficult to socialize because the parent-child relationship does not serve to motivate behavior (Kochanska, 1997). These models of antisocial behavior also implicate childrearing and family context, but consider basic personality characteristics as a necessary, albeit not sufficient, feature. In contrast, Patterson (1982) and others (e.g., Greenberg et al., 1993; Reid, 1993; Sroufe, 1990; 1997) emphasize childrearing or qualities of the parent-child relationship as central. Although infant irritability and/or symptoms of hyperactivity are also posited to play a role in Patterson's formulation, coercive exchanges between young children and their parents are viewed as a necessary ingredient for long-term antisocial behavior that then leads to other problems in school and with peers, ultimately becoming more serious in adolescence. Several other aspects of the parent-child relationship have also been proposed as important ingredients in the development of externalizing behavior in young children, including: maternal


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unresponsiveness (Martin, 1981; Shaw, Keenan, & Vondra, 1994) and insecure attachment (Erickson, Sroufe, & Egeland, 1985); ineffective, inconsistent, or negative parental control strategies (Belsky et al., 1996; Campbell et al., 1996); intrusive caregiving (Carlson et al., 1995); lack of positive involvement (Gardner, 1987, Pettit, Bates, & Dodge, 1997); modeling of angry conflict resolution strategies (Weiss, Dodge, Bates, & Pettit, 1992); and, unwillingness to comply with parental requests in the absence of a warm emotional relationship (Kochanska, 1997). Undoubtedly several of these parent-child interaction processes at the emotional and social-cognitive levels are going on simultaneously, and together they converge to predict problems. However, research is needed to tease apart those aspects of the parent-child relationship that serve as mechanisms of problem persistence from those that are merely markers of a poorly functioning and unsupportive relationship. These various models of the emergence of aggressive, noncompliant, and poorly regulated behavior in young children can be reconciled because all implicate child, parenting, and contextual factors as relevant, despite moderate differences in emphasis. Moreover, it is widely recognized that the dual focus on temperamental or within child characteristics and features of the family context imply transactional processes and implicate environmental and genetic influences, and gene-environment interactions. This is no longer a debate about nature and nurture (Rutter, 1997), but one about the complex mechanisms that link genetic predispositions with specific childrearing and other social experiences, some actively sought by the child. Developmental Pathways. Recent research focuses on developmental pathways that highlight the different trajectories that children with early signs of problems may follow (Cicchetti & Rogosch, 1996). This issue is partly illustrated by the discussion about the developmental course of early externalizing symptoms. Many young children show behaviors analogous to symptoms of ADHD (e.g., fidgety, overactive, restless, difficulty awaiting turn), ODD (e.g., tantrums, argumentative, noncompliant), and at least mild CD (e.g., aggression toward peers). However, most children who show these behaviors, either in isolated form or for a short time in toddlerhood or at preschool-age will not meet criteria for any of


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these disorders by school entry. Some children, however, who show a constellation of these behaviors at relatively high levels in early childhood, especially in the context of family risk, will continue to have problems in middle childhood and beyond (e.g., Moffitt, 1990; Pierce, Ewing, & Campbell, 1999). Although Moffitt and colleagues (Caspi et al., 1995; Moffitt et al., 1996) approach early behavioral markers of problems from a temperament perspective, their data are consistent with the notion that continuity is more likely to be evident when constellations of disruptive behavior are identified early. Testers rated children's behavior at age three while administering a battery of psychological tests. A factor describing "lack of control", characterized by poorly regulated expression of impulses, low persistence, and negative response to challenge was derived. Caspi et al. (1995) consider this to be an index of temperament, but it may just as easily be a reflection of early oppositional and impulsive behavior. High scores on this dimension predicted externalizing problems as rated by parents and teachers at ages 9, 11, 13, and 15 indicating modest stability across informants and time. These data have also been used to examine multiple pathways to antisocial behavior, as it is one of the few longitudinal studies in which young children have been followed from early childhood through adolescence and young adulthood, with repeated assessments of symptom patterns and self-reported delinquent behavior (e.g., Moffitt, 1993a; Moffitt et al., 1996). Moffitt and colleagues identified four groups of boys who differed with respect to antisocial history and developmental course: 1) a life-course persistent group who began early and persisted in their antisocial and aggressive behavior into adolescence; 2) an adolescent onset group who did not display problem behavior early, but became somewhat aggressive and antisocial in adolescence; 3) a recovered group who started out as highly antisocial in early childhood, but was no longer aggressive by adolescence; and 4) a comparison group of boys who were not antisocial or aggressive. Clearly the task for researchers is to determine why some of these boys recover, while others go on to experience continuing problems. Data from Moffitt et al. (1996) indicate that boys in the persistent and recovered groups received similarly high ratings on the "lack of control" factor at ages 3 and 5, but that


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the recovered boys were not as alienated from their families as those who continued on a pathway toward more serious problems, and their families were less dysfunctional. At age 18, recovered boys were less likely to have dropped out of school, to be unemployed, to have delinquent friends, or to abuse alcohol and drugs than those in the life-course persistent group. Boys in the life-course persistent group came from families marked by chronic family adversity, as reflected in low parental educational and occupational status, low income, teen pregnancy, single-parent status, large family size, and poor maternal mental health (Moffitt, 1990). Although Moffitt tends to emphasize the role of child regulatory abilities, the Dunedin data also indicate that the early starter group experienced more psychosocial adversity than the non-disordered controls at each of the 6 assessments between the ages of 3 and 13. Although the role of parenting was not examined in this study, results suggest an ongoing transactional process between early child behavior and differing levels of parental support and family adversity. In addition to the two groups of boys with early problems, boys whose antisocial behavior began later lived in less adverse family settings and were less extreme than the persistent group on a number of behavioral measures, suggesting a less severe, possibly time-limited foray into adolescent rebellion and experimentation that does not presage long-term maladjustment. Patterson, using data from the Oregon Youth Study, also identified a group of "early starters" whose problems escalated and worsened during childhood and adolescence (Patterson & Yoerger, 1997), in contrast to the "late starters" who appear to resemble Moffitt's adolescent-limited group. He argues that boys in the late onset group were raised in more responsive families in which parents provided adequate limit-setting, monitoring, and models for prosocial behavior in childhood, but had difficulty competing with peer influences in adolescence. In contrast, boys in the early onset group were raised in families with multiple problems that included poor parenting and family stress. Based on the arguments of Patterson and Moffitt, the DSM-IV now includes childhood onset and adolescent onset subtypes of Conduct Disorder, on the assumption that those with a diagnosis of childhood onset type are at higher risk for continuing problems including antisocial personality disorder in adulthood.


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More recent longitudinal data from the High Risk Study (Aguilar, Sroufe, Egeland, & Carlson, in press) also confirms that low income children followed longitudinally from early infancy to adolescence can be divided into four groups: never antisocial, childhood limited, adolescent limited, and life course persistent. However, unlike Moffitt's data, findings from the Minnesota study implicate early family risk, rather than temperamental difficultness and cognitive deficits, as predictors of ongoing problems. Shaw and colleagues (Shaw, Gilliom, & Giovennelli, 2000) also studied a sample of 300 low-income boys facing many of the same stressors as Moffitt's group of early starters. Using a cut-off score at or above the 90th percentile on the CBCL Externalizing factor at age 2, mothers rated 6% of the boys as showing clinically-elevated levels of conduct problems. Of these, 63% remained above the 90th percentile at age 5, and 97% remained above the median. At age 6, 62% remained in the clinical range and 100% (all 18 or 6% of the initial sample) remained above the median. False negative rates were relatively low for the same factors. Only 13 and 16% of boys below the 50th percentile on the Externalizing scale at age two moved into the clinical range at ages five and six, respectively. When clinically-elevated groups were formed at age two based solely on CBCL items involving aggressive behavior, and the outcome variable was the narrow-band CBCL Aggression factor (comprised of aggressive, destructive, and oppositional symptoms) at age 5, prediction to clinical outcome was improved further. Campbell and colleagues, studied two cohorts of hard-to-manage preschool children, and reported that children whose early symptoms of hyperactivity and aggression were elevated across contexts (home and preschool), and who were living with high levels of ongoing family stress and negative parenting were more likely to continue to have problems at school entry (Campbell, 1990; Campbell, 1997; Campbell et al., 1996). Taken together, then, the results of these studies of young children with externalizing problems beginning as early as age 2 or 3 indicate moderate to strong continuity when symptoms of disruptive behavior are frequent, relatively severe, and pervasive, and the family environment is characterized by high psychosocial adversity. Moreover, those youngsters who are truly


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at risk for long-term problems appear to show co-occurring signs of both hyperactivity-impulsivity and aggressive-noncompliant behavior (e.g., Campbell et al., 1994; Loeber, 1988; Moffitt et al., 1996; Speltz et al., 1999). Depending upon the nature of the sample (e.g., clinical, high risk, or population-based), how problem behavior is defined and measured, and the length of the follow-up period, different proportions of children will show stable problems from early to later childhood. Speltz et al. found that 71% of their clinical sample of boys who met diagnostic criteria for ODD at age 4 continued to meet DSM-IV criteria for an externalizing disorder two years later. Richman and Campbell both reported rates of about 50% stable problems from age 3 to middle childhood in non-clinical groups with high levels of initial symptoms. In the Moffitt et al. longitudinal, epidemiological study, the life-course persistent pattern was followed by about 7% of the sample assessed from age 3 until age 18. This figure is similar to the 5% of chronically aggressive and antisocial boys identified by Nagin and Tremblay (1999) and the 6% of persistent aggressive children identified by Shaw and colleagues. These data, then, indicate both high rates of remission, and of persistence; they also underscore the importance of identifying high risk groups for targeted prevention programs (Bennett et al., 1998). Young Behavior Problem Children in Multi-Problem Families Based on the studies cited above, it is clear that many children who develop early and persistent externalizing problems come from families marked by risk factors in multiple domains (Campbell, 1997; Greenberg et al., 1993; Moffitt, 1990; Shaw et al., 2000). Child behavior in infancy and toddlerhood may be marked by high levels of negative and angry affect that is poorly regulated and may be manifest in symptoms such as impulsivity, hyperactivity, aggression, and noncompliance. These occur in the context of a poor mother-child relationship, often characterized by ineffective discipline strategies, as well as limited warmth and involvement. These findings underscore the dual emphases on temperament and relationship factors discussed earlier. In addition, high levels of family stress tend to co-occur with child and parenting problems, further exacerbating difficulties in the family system.


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Methodologically, both variable- and person-oriented approaches have been used to quantify this pattern from early childhood through adolescence. Initially, the majority of this research was carried out using a variable-oriented approach. Increases in the rates of conduct problems were found to be a function of heightened family adversity. The family adversity hypothesis was initially proposed by Rutter and colleagues (1975) in their Isle of Wight study, and emphasized the quantity of stressors rather than the unique effects of individual stressors on child maladjustment. Rutter et al. (1975) found a multiplicative increase in the rates of externalizing problems as a function of the number of risk factors present across the following domains: sociodemographic risk, maternal psychiatric adjustment, paternal criminality, and marital discord. None of these family stressors was associated with an increased likelihood of child behavior problems in isolation; however, when two or more stressors were present, the risk of child behavior problems was found to increase two- to four-fold in two diverse communities, an inner London borough and the Isle of Wight. This finding has been replicated across cultures (Sanson, Oberklaid, Pedlow, & Prior, 1991), over time (Sameroff, Seifer, Zax, & Barocas, 1987), and, importantly, with young children (Sameroff et al., 1987). Recently, concerns have been raised about the limitations of analyzing individual pathways using variable-oriented approaches that rely exclusively on inferential statistics to categorize heterogeneous groups of children together (Cicchetti & Rogosch, 1996; Richters, 1997; Wangby, Bergman, & Magnusson, 1999). As a result, there has been a growing interest in the use of person-oriented statistical methods, which emphasize trajectories of similar groups of children rather than variables. A person-oriented approach appears to be well suited to the diversity of potential pathways antisocial children travel. As noted earlier, child (Sanson et al., 1991), parenting (Belsky et al., 1996; Campbell et al., 1996; Gardner, 1987), family (Jouriles et al., 1991), and extra-familial (Shaw et al., in press) factors have been related to conduct problems beginning as early as the toddler and preschool years. The number of factors and potential trajectories predictive of conduct problems only increases as children's ecological contexts expand after the preschool period, when new factors such as social information


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processing (Dodge, Lochman, Harnish, Bates, & Pettit, 1997), parental monitoring (Patterson et al., 1989), and peer relations (Coie, Dodge, & Kupersmidt, 1990) become important. Thus, it is likely that there are many trajectories associated with antisocial outcomes. This has not prevented researchers from attempting to isolate the more common pathways leading to conduct problems among school-age children and adolescents using person-oriented techniques such as cluster analysis (Cairns, Cairns, & Neckerman, 1989; Nagin & Tremblay, 1999). However, relatively few such studies have been carried out with young children (Campbell et al., 1996; Shaw et al., 1996). One exception to this is a study by Belsky et al. (1996), who used cluster analysis to identify a group of "troubled" families from a sample of infants. Families marked by persistent conflictual parent-child interaction and family and social adversity at 15 and 21 months were found to have toddlers with the highest externalizing problem scores at 18 months, in comparison to families identified as nonproblematic or to families who were troubled only at 15 or 21 months. This study highlights the need to look beyond the measurement of individual variables in assessing risk for early behavior problems. By using a person-oriented approach, Belsky and colleagues were able to identify a constellation of families (rather than variables) that shared a common set of risk factors that, in turn, were related to externalizing problems in early childhood. The Belsky et al. study provides an example of how to use a person-oriented approach to examine the correlates of early externalizing problems, but studies that include at-risk samples followed over a longer period of time are needed to validate the use of such techniques. The analyses to be summarized briefly below were conducted to extend the use of a person-oriented approach by applying cluster analytic techniques (Bergmann & Magnusson, 1996; Ward, 1963) to two at-risk samples of young children. Although both samples of children may be considered of high-risk status, children were recruited at different ages, using different criteria, and they vary in terms of family socioeconomic characteristics. Using a common method, our goal was to determine whether a combination of child, parenting, family, and sociodemographic risk factors measured at study entry clustered together in meaningful ways,


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whether the clusters replicated across different samples, whether they had meaningful concurrent correlates, and whether cluster membership predicted externalizing outcomes at school entry and middle childhood (Campbell & Shaw, 1999). In the Campbell data set, boys were recruited between the ages of 3 and 4 from local preschools and child care centers in the Pittsburgh area (Campbell et al., 1991; Campbell et al., 1994). Teachers rated all the boys in their classrooms whose parents gave consent on a brief questionnaire which assessed inattention, overactivity, and impulsivity according to DSM-III criteria (American Psychiatric Association, 1980), in use when this longitudinal study began. Risk was defined as early emerging signs of ADHD symptoms, as indicated by symptom scores that approximated DSM-III criteria for ADHD. Boys from the same classrooms with scores below the cut-off were also recruited for participation. Most boys with elevated symptoms of ADHD also were rated high on aggression and peer problems. The final sample consisted of 112 boys (mean age = 46 months, range = 29-58 months) of whom 69 were considered at high risk for persistent problems. Children were observed and tested at home, in the laboratory, and in their preschool classrooms and interview and questionnaire data were obtained from mothers and teachers. Over 90% of the families were followed up at ages 6 and 9 at which time mothers and teachers (age 6 only) completed questionnaires. A cluster analysis (Ward, 1963) was performed on nine intake measures (standardized prior to clustering) that cut across domains of risk: child risk (history of pregnancy and birth complications; history of fussy-difficult temperament in infancy; inattention-hyperactivity; aggression-noncompliance; Stanford-Binet IQ, Form L-M); maternal parenting risk (observed negative maternal control in the laboratory during a toy clean-up procedure; see Campbell, 1994); family risk (maternal depressive symptoms; stressful life events; see Campbell, 1994); and sociodemographic risk (SES). Details of measures may be found in prior publications (Campbell, 1994; Campbell et al., 1991; 1994). A five cluster solution seemed most parsimonious and made the most conceptual sense. Cluster one was a multiple risk group with elevated scores across domains of risk. Children in this cluster (n=10,


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9%) had higher rates of pregnancy and delivery complications, higher ratings of child hyperactivity and aggression, lower child IQ scores, lower family SES, more negative and controlling maternal parenting during a clean-up task, and higher rates of maternal depressive symptoms, stressful life events, and single-parent status. A second cluster of only 6 boys (5%) represented a child risk group, with elevated scores only on difficult temperament, pregnancy/delivery complications, and ratings of hyperactivity and aggression. In contrast, cluster 3 reflected a family risk group (n=13, 12%), with risk limited to observed negative maternal control, and high rates of depressive symptoms and stressful life events. The two remaining clusters, albeit the largest ones, were both low risk groups, one with no risk factors (no risk, n=38, 34%) and one with only moderately elevated scores on hyperactivity (low risk, n=45, 40%). At intake, boys in the multiple risk group received the highest scores relative to boys in the other clusters on independent observations of inattentive and restless behavior during testing at home, on observed aggressive behavior in preschool, and on ratings of negative affect and resistance in the laboratory during toy clean-up. At the age 6 follow-up, mothers rated boys in the multiple risk cluster as showing more internalizing and externalizing symptoms on the Child Behavior Checklist, and as lowest in social competence relative to boys in the two low risk clusters and boys in the family risk cluster. Boys in the child risk cluster were also rated as higher in externalizing symptoms and lower in social competence than those in the no risk group. Teachers also rated multiple risk boys as high in externalizing problems and low in social competence, with the boys in the child risk group also receiving elevated externalizing scores and low social competence scores relative to the no risk cluster. At the age 9 follow-up, the boys in the multiple risk cluster continued to receive the highest ratings on externalizing symptoms. Thus, over time, measures, and contexts (home, school), boys in the multiple risk cluster showed the poorest functioning and the most problems relative to boys in the other clusters. Data for the second set of analyses come from Shaw’s longitudinal study of precursors of externalizing problems. More details on methods can be found in earlier publications (Shaw, Winslow, & Flanagan, 1999; Shaw, Winslow, Owens, & Hood, 1998). Low-income mothers and their infants were


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recruited from the Women, Infants, and Children (WIC) Nutritional Supplement Program of Allegheny County, PA. Of 310 families seen at the age 1-1/2 visit, data were available for 306 participants at the age 2 visit and 279 participants at the age 6 visit (10% attrition). At the first assessment, mothers were between 17 and 43 years of age (M = 28) and 62% were married or living with a partner. The sample was primarily European American and African American (54% and 40%, respectively). Families participated in laboratory visits when boys were 1½, 2, and 6 years of age. A home visit was also conducted at age 2. Mothers and sons completed interactive tasks during laboratory assessments. Mothers completed questionnaires on child and maternal functioning and family circumstances at each visit. At age 6, 189 teachers completed questionnaires on child behavior. Nine risk factor composites obtained from the age 1-1/2 and/or 2 assessments were subjected to a cluster analysis from the following four domains: child characteristics (maternal ratings of infant difficultness; hyperactive behavior; aggressive and oppositional behavior); maternal parenting behavior (observed parental nurturance and organization of the home environment from the HOME [Caldwell & Bradley, 1984], and observed maternal rejecting behavior during a toy clean-up task); family context (maternal depressive symptoms; stressful life events); and sociodemographic risk (family income; neighborhood dangerousness). Ward's cluster method was used and five clusters were identified, to some extent paralleling the prior analysis. Cluster one represents a multiple risk group with risk factors present across domains. Children in cluster one (n = 45, 18%) had elevations on infant difficultness, aggression, and hyperactivity; parenting marked by low levels of nurturance and less structure of the home environment; a family context marked by elevated rates of maternal depressive symptoms and negative life events, low income, and neighborhood dangerousness. A second cluster of 38 families (15%) represents a child/parenting risk group, with high scores on measures of infant difficulty and particularly aggression and hyperactivity, and maternal rejecting parenting. Cluster three included a relatively large group (n = 75, 30%) marked only by neighborhood risk and below-average income. Cluster four is a no-risk group


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with no elevated scores on any risk factor (n = 86, 33%). Cluster five contains a small set of families (n = 6, 2%) who show child and family risk factors, as indicated by elevated child aggressivity and hyperactivity, maternal depressive symptoms and life events, and extreme neighborhood dangerousness. Boys in the multiple risk cluster received the highest score on an independent measure of child noncompliance rated from videotapes at the initial assessments (ages 1-1/2 and 2). At age 6, mothers rated boys in the multiple risk group as highest on both internalizing and externalizing problems relative to the no risk group; boys in the child/parenting and neighborhood risk groups were also somewhat elevated relative to the no risk cluster. However, teachers rated boys in the child/family risk and neighborhood risk groups highest on externalizing problems relative to the no risk cluster; boys in the multiple risk cluster were seen as less cooperative. These data show surprising convergence across two cohorts of young boys, despite differences in age at study entry, demographics, recruitment procedures, measures, and definitions of risk. In general, in both cohorts we identified a multiple risk group that was elevated on maternal ratings of both hyperactivity and aggression, experienced more negative or less positive parenting, and was exposed to more maternal depressive symptoms, stressful life events, and sociodemographic risk. Across independent concurrent and follow-up measures, these young boys were observed to show the most restlessness, noncompliance, and aggression at study entry, and to be rated by both mothers and teachers as showing more behavior problems and lower social competence at follow-up relative to other clusters of boys. These two clusters of boys experiencing multiple risk factors in early childhood showed a pattern of elevated problems across settings, reporters/observers, and time suggesting that they are the group most likely to be at risk for continuing problems in adolescence. Although it is true that boys in the child risk cluster in study 1 and the child/parent and neighborhood risk clusters in study 2 also showed elevated scores relative to boys in the low-risk clusters, their patterns of differences were less consistent, suggesting that they are also less likely to be at highest risk for continuing problems. These results are consistent with the view that only a small proportion of children


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identified on the basis of early risk, are likely to continue to have major problems in middle childhood or adolescence (Bennett et al., 1998; Moffitt et al., 1996; Nagin & Tremblay, 1999; Patterson & Yoerger, 1997). Those most likely to continue on a pathway toward externalizing problems in adolescence seem to be those boys experiencing not only early risk, but risk that cuts across child, parenting, family, and sociodemographic domains. Thus, from a transactional perspective, children with early problems may be able to overcome their difficulties, in the absence of parenting and family risk, possibly because better functioning parents serve as positive role models and provide more positive and less coercive parenting (Patterson & Yoerger, 1997). Similarly, children with less serious early problems who are not seen as hard-to-manage in toddlerhood or the preschool years may be less susceptible to early family risk because they are able to garner support from others in their social network or because family risk may be less persistent in the absence of co-occurring early child problems, which may exacerbate family stress (Mash & Johnston, 1983). Children living in dangerous neighborhoods may be at risk for problems, especially in middle childhood and adolescence, but they may also be protected from some of these risks when they live in families in which parents provide relatively strict supervision and monitoring and where family stress is only moderate. Thus, the combination of multiple risk factors may be necessary, or at least sufficient, conditions for continuing problems. This possibility has implications for future research directions and for public policy. There are certainly limitations to these data and we do not want to over-interpret findings. The obvious limitations include small n's, only relatively short-term follow-up, inclusion of children and families who are not at the extremes in high risk status, and a focus exclusively on boys. However, these data do underscore the need for large-scale, prospective longitudinal studies that begin with high risk groups with multiple risks across domains and use more indepth, developmentally-appropriate, and multi-source observational and interview measures to assess development in context.


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Directions for the New Millennium In our final section we will discuss future directions that have the potential to inform basic and applied researchers about the mechanisms underlying the development of conduct problems in early childhood. After discussing the needs for prospective studies and utilizing a developmental framework, we focus on areas that have generated theoretical speculation but relatively little empirical validation of their significance with young children because of methodological (e.g., physiological measurement of emotion regulatory function) or substantive (e.g., role of ethnicity) challenges. We conclude by discussing the implications of the research for social policy. Prospective Studies It is evident that prospective, longitudinal studies of high risk children from toddlerhood to adolescence are still needed, with risk defined in a multifaceted manner that includes child characteristics (e.g., early signs of both hyperactivity and aggression), parenting risk, poor family functioning, and sociodemographic risk.

Such studies need to provide indepth assessment of various facets of parenting

and the parent-child relationship in order to disentangle potential causal mechanisms (e.g., coercive parenting, insecure/disorganized attachment) from markers of a poor relationship (e.g. harsh discipline). In addition, the issue of gender needs to be addressed. Do the same relations among variables emerge for boys and girls?

Are high risk girls more likely to look aggressive and impulsive in early childhood, but

then become more anxious and depressed later? Furthermore, studies of high risk toddlers must consider biological factors as well as parenting practices and family risk. Further, attention must be paid to both cultural and neighborhood factors that may moderate the definition of risk itself, as well as the nature of parenting and family processes. To date, studies of high risk children have focused almost exclusively on boys and have not considered multiple aspects of parenting or social context. Clearly, this is needed if we are to identify apppropriate subgroups of young children for early intervention (Bennett et al., 1998). Applying a Developmental Perspective


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During the last decade, there has been a growing interest in integrating our knowledge of developmental processes with the study of child psychopathology. Part of the marriage between developmental psychology and psychopathology has involved taking advantage of normative milestones of childhood to capture points of transition. The FAST Track Project (Conduct Problems Prevention Research Group, 1992) is a prime example of this approach, in which the transition to full-day schooling was used to study the onset and prevention of serious conduct problems. Several prospective studies have also been initiated in early childhood to take advantage of transitions in the parent-child relationship. The majority of these have focused on the transition to the terrible twos (Shaw & Bell, 1993). During the first year, the parent’s primary challenge is to meet the infant’s needs in a sensitive and responsive manner. However, in the second year with the advent of toddling, movement into forbidden space, and reaching for dangerous objects, the equilibrium of the relationship becomes disrupted. In response, parents initiate control strategies, which in turn, are often met by expressions of undirected aggression and oppositional behavior by the toddler, creating greater stress in the parent-child relationship. There are now at least four ongoing, nonintervention projects whose aim has been to take advantage of this point of transition which captures the initial unfolding of early conduct problems beginning prior to or at age two (i.e., Belsky et al., 1996; Calkins, 1998; Olson,1999; Shaw et al., 1999). We have reviewed findings from the Belsky and Shaw studies, while the projects of Calkins and Olson are just beginning data collection.

Still, there remains a dearth of prevention/early intervention studies in early childhood that

have been informed by developmental theory to guide their timing and focus on stage salient developmental issues. Studies that capitalize on the challenges of parenting in the second and third years of life are recommended, particularly among families characterized by risk factors across child, family, and sociodemographic domains.

Finally, none of the aforementioned designs can tease apart genetic from environmental influence. While reports on the relative and joint influence of genes and environment on early conduct problems have begun to emerge, there is a need for developmentally-sensitive studies


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initiated in early childhood that incorporate genetic designs. In particular, adoption studies have the potential to uncover evocative gene-environment correlations between heritable child characteristics (e.g., impulsivity, activity) and environmental responses (e.g., rejecting parenting), and gene x environment interactions which involve the potential moderating effects of the environment in relation to genetic risk for problem behavior (e.g., parenting and marital quality of adoptive parents) (O’Connor, Deater-Deckard, Fulker, Rutter, & Plomin, 1998). Adoption studies may provide a greater reward for prevention and treatment than twin studies (i.e., limited to heritability estimates) because they can advance our understanding of the potential and limits of the environment to modify genetic liability. Biological processes and the development of conduct problems Initial studies employing behavioral genetic designs to study the development of antisocial behavior reveal significant genetic contributions to early conduct problems (Leve, Winebarger, Fagot, Reid, & Goldsmith, 1998; Schmitz, Cherny, Fulker, & Mrazek, 1994). Evidence for genetic influences on antisocial trajectories leads naturally to a consideration of biological processes through which genes exert their effects. Until recently, however, efforts to understand the contributions of biology to childhood externalizing problems have been constrained by the invasiveness of biological assays and by fears that biological research would engender deterministic conceptions of antisocial behavior. Advances in measurement techniques and increasing appreciation of the complex interplay between nature and nurture in shaping behavior have produced a small but growing literature on the psychophysiological correlates of early conduct problems. The promise of this research area lies in its potential to provide deeper understanding of within child risk factors and to illuminate transactions among genes, behavior, and environment that influence antisocial development across the lifespan.


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To date, research suggests that child externalizing behaviors per se are not linked directly to biological mechanisms. Rather, the effects of biological factors on early externalizing behaviors appear to be mediated through their influence on adaptation to stage-salient developmental challenges, including the development of emotion regulation and impulse control. For example, resting heart rate, a general indicator of autonomic arousal, has been related to antisocial behavior in child samples. Of particular relevance to the present discussion, Raine and colleagues (Raine, Venables, & Mednick,1997) found that low resting heart rate at age 3 was a marker for aggression at age 11. Low resting heart rate has also been associated with lack of empathy (Zahn-Waxler, Cole, Welsh, & Fox, 1995) and fearlessness (Scarpa & Raine, 1997), and it is thought that these characteristics account for the relationship between underarousal and antisocial behavior. Heart rate is under dual, reciprocal control of the sympathetic and parasympathetic branches of the autonomic nervous system. The vagus, the primary parasympathetic pathway to the heart, rapidly regulates cardiac output during environmental challenge. Porges and colleagues (Porges, Doussard-Roosevelt, Portales, & Greenspan, 1996) observed that poor vagal modulation at 9 months of age was related to externalizing problems at 3 years of age. Cortisol levels also provide information about the allocation of metabolic resources in the face of environmental stressors. Cortisol reactivity, an index of the physiological stress response, has been linked to externalizing symptoms in preschool boys (Tout, de Haan, Campbell, & Gunnar, 1998). Finally, processes in the cerebral cortex may be relevant to the development of externalizing problems at several levels. First, imbalances in the activation of left and right hemispheres are thought to produce stable motivational tendencies related to approach and withdrawal, which in turn may moderate risk for aggressive, defiant behavior (Fox, Schmidt, Calkins, Rubin, &


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Coplan, 1996). Second, neurological abnormalities in the temporal and frontal areas of antisocial adolescents and adults suggest that deficits in inhibitory control may confer risk for the development of externalizing problems in childhood (Moffitt, 1993b; Pennington & Bennetto, 1993). This brief review highlights the diversity of approaches employed and insights gained in initial studies of the biological correlates of early conduct problems. Advances in brain imaging, molecular genetics, and other techniques will certainly increase understanding of antisocial development in the years to come. Just as important as identifying biological contributors to externalizing behavior, however, is considering how these processes transact with contextual factors over time to influence risk. For example, both biological and environmental factors are thought to give rise to individual differences in emotion regulation (Calkins, 1994). However, well-designed investigations of how parenting or other environmental processes may be associated with biological processes in the development of self-regulation have not been conducted. Longitudinal studies beginning in infancy and involving multiple measures of neurobiological functioning along with assessments of emotion regulation, impulsivity, and other child characteristics, as well as measures of parenting, family stress, and other contextual factors, would provide a more integrated picture of the origins and course of childhood conduct problems. Neighborhood Influences One of the surprisingly consistent findings from Shaw’s cluster analysis was the degree to which children in the neighborhood risk group showed later conduct problems and social skills deficits at home and at school. In and of itself, low income may represent a less accurate gauge of family context risk because of intra- and extra-familial variability in financially-impoverished environments (i.e., housing and both intra- and extra-familial support may be adequate). However, high levels of neighborhood


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dangerousness nearly ensure that risk factors outside of the home are present, and as is evident from our data, affect young children. At a direct level, young children living in such neighborhoods may be at an increased risk for conduct problems due to a greater exposure to antisocial attitudes and behaviors, which socialize children in deviant behaviors (W.Wilson, 1996). Neighborhood quality may also influence relationships among peers, parenting, and early conduct problems. It is only recently that researchers have recognized the importance of studying peer relations within the context of the neighborhood (Dishion, French, & Patterson, 1995; Kupersmidt, Burchinal, & Patterson, 1995), the effects of which appear to be more pronounced in impoverished settings. The vast majority of research related to peer influences on child conduct problems has been carried out with same-age classmates in school settings. However, it is in the neighborhood context in which young children have been shown to have the greatest amount of exposure to aggressive peers (Sinclair, Pettit, Harrist, Dodge, & Bates, 1994). Similarly, parents who are understandably worried about the influence of older peers in such neighborhoods may be overly restrictive and harsh in parenting their offspring. In the short term, this style of parenting may prove to keep children under control (Deater-Deckard, Dodge, Bates, & Pettit, 1996), but in the long term promote the use of aggression and delinquent activities through modeling and negative reinforcement (Patterson, Reid, & Dishion, 1992). Neighborhood effects would be expected to emerge as children become more involved with peers and adolescents in the neighborhood without supervision from parents (Brooks-Gunn, Duncan, Klebanov, & Sealand, 1993). Research at the community level, which involves testing associations between rates of conduct problems and neighborhood official statistics (e.g., police crime records, census tract data on public housing), suggests that beginning around age 5 or 6, differences in conduct problems in children living in disadvantaged neighborhoods become more pronounced even after controlling for family sociodemographic characteristics (Brooks-Gunn et al., 1993; Chase-Landsdale & Gordon, 1996; Kupersmidt et al., 1995). However, few studies involving young children have examined the effects of neighborhood influence at


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the level of the individual using family’s perception of neighborhood safety. In the few studies that have tested the effects of neighborhood quality at the individual level, support for its independent contribution has been found (Winslow & Shaw, 1996; Shaw et al., 1999). However, more research in this area is needed with young children to better understand the mechanisms underlying this relation, some of which are discussed below. Culture and Ethnicity In the United States, neighborhood quality and ethnicity are confounded because of the over-representation of ethnic minority families living in impoverished conditions. Nonetheless, it is worth discussing the issue of ethnicity separately because of idiosyncratic issues associated with minority status. In considering the meaning of ethnicity, it is immediately apparent that this status typically refers to people of color. Because of space limitations, we will focus on African American (AA) families. However, similar issues apply to other people of color within the United States (e.g., Latino). The impact of ethnicity also reflects the difficulties experienced by minority groups when they attempt to integrate and assimilate into American society. For AA families, persistent discrimination, exclusion, and oppression within American society make their experience qualitatively different from other ethnic groups that have immigrated to the United States (Kohn & Wilson,1995). Socioeconomic and historical contexts within AA culture create unique life experiences; however, there is a striking lack of research that considers the impact of such experiences on the development of children. In order to ensure an accurate understanding of children growing up in different cultural contexts, the variations within cultural groups must be considered rather than discarded as noise or minor variations. It is only recently that researchers have begun to investigate the effects of ethnicity on child conduct problems substantively, rather than as a factor to be “controlled.” In some studies where ethnicity was “controlled”, sociodemographic factors have been found to account for differences in antisocial behavior between European American (EA) and AA families (Hinshaw & Park, in press). However, differences persist in other studies even after accounting for sociodemographic characteristics (Dodge et al., 1995;


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Winslow & Shaw, 1996). Research on family influences needs to recognize differences between AA and EA families in structure and stability, specifically the higher rates of single-parent status and the greater number of changes in family structure (Kellam, Adams, Brown, & Ensminger,1982). It is unclear if such differences in the quantity and fluidity of family structure influence the course of early conduct problems, particularly at times of developmental transition. In terms of child characteristics, it also has been shown that AA children demonstrate greater hostile attributional bias than EA school-age children, even after controlling for sociodemographic factors (Dodge et al., 1997). It remains unclear whether differences in social information processing accurately reflect the way AA youth are treated by peers, and perhaps serve an adaptive function, and whether such “biases” are associated with conduct problems as they are in EA children with similar attributional patterns. Research is also needed that investigates the emergence of differences in social information processing between AA and EA children across age and context (e.g.,day care, preschool). Differences in parenting styles and their relation to child conduct problems have also been noted in EA and AA families. AA families are more likely to employ an authoritarian style that emphasizes the importance of control and child compliance over warmth. This style has been associated with negative outcomes among predominantly EA, middle-class families (Baumrind, 1971). Ironically, Baumrind (1972) was perhaps the first investigator to note that an authoritarian style may have adaptive significance for AA families. For EA children, authoritarian parenting was related to low independence and mid-range scores on social responsibility, whereas for AA children, authoritarian parenting was associated with high scores on self-assertion and independence, particularly for girls. It is only recently that other researchers have investigated differences in parenting between EA and AA families with respect to antisocial outcomes (Winslow & Shaw, 1996). Deater-Deckard and colleagues (1996) found that differences in the use of low to moderate corporal punishment were differentially related to risk of conduct problems for EA and AA children. For EA parents, any level of corporal punishment was associated with conduct problems; for AA parents, there was no relation between the use of corporal


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punishment and antisocial behavior unless the punishment reached severe levels. Research on cultural differences in parenting with respect to short- and long-term outcomes are sorely needed beginning in early childhood across low and middle-class environments. For instance, it is unclear how cultural differences in childrearing influence the transition to the terrible twos and what consequences these have for AA children’s later adjustment. Neighborhood quality may help to explain the divergent outcomes associated with strict parenting in AA and EA families. It may be that a parenting style that emphasizes firm control over explicit warmth is more adaptive to the immediate risks of the neighborhood environment of low SES AA families. This finding is consistent with AA children’s tendency to demonstrate higher rates of hostile information processing, which may also accurately reflect their greater likelihood of encountering dangerous situations and the influence of an authoritarian parenting style. However, our understanding of the processes involved is based more on conjecture than empirical evidence, as few studies have been undertaken to investigate these issues prior to school entry. These processes require careful investigation in the coming years. Social Policy It seems clear from this discussion that it is possible to identify high risk children living in high risk environments, and that those with early onset behavior problems are likely to be at highest risk for later problems in adjustment. It is also evident that problems can often be identified prior to age four or five when children often begin Head Start or kindergarten. The arguments for subsidized high quality child care for very young children with early signs of behavior problems, living in high risk family and neighborhood contexts (Ramey & Ramey, 1998; Scarr, 1998) is strengthened by recent reports from the Abecedarian Project (Ramey & Ramey, 1998). Of course, these arguments are not new. Zigler has been arguing for the expansion of Head Start and similar programs (Zigler & Styfco, 1993) for years, and the renewed emphasis on early intervention appears to be taking hold. However, it is only recently that universal early interventions such as Head Start have been combined with targeted prevention to begin to address the wide range of problems often experienced by young children at high risk for later problems.


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More research is needed to assess the impact of comprehensive, prevention programs focused on two and three year olds with early symptoms of externalizing problems residing in dysfunctional family settings. For example, the FAST Track Model (Conduct Problems Prevention Research Group, 1992) might be expanded downward to target parents and children, as they cope with the transition from infancy to toddlerhood and struggle with issues of compliance, autonomy, cooperation in the peer group, and the regulation of emotion, stage salient developmental tasks that may exacerbate parent-child conflict, especially in the context of high levels of family risk. Prevention programs for children at risk for language difficulties also would be easy to implement during the toddler period (Hart & Risley, 1995). This is an important issue given the co-occurrence of behavior and language problems in preschool-age children. A multi-level model similar to FAST Track has already been developed and shown to be effective for conduct-disordered adolescents, which may have even more relevance to the problems of living that our multiple risk families experience. Multisystemic therapy (MST, Henggeler and Bourdin, 1990) draws from a variety of treatment modalities, including family-based interventions to modify parenting strategies, and more concrete assistance with problems of living, such as helping the family find adequate housing, to address contextual processes that adversely affect parent and child functioning. Originally used with conduct disordered adolescents, efforts are underway to use MST with toddlers and their families (Henggeler, personal communication, October, 1999). Summary We have discussed the early emergence of symptoms defining ADHD, ODD, and CD and how their co-occurrence in toddlerhood and the preschool period, especially in the context of family stress and harsh parenting may place young children, especially boys, on a pathway toward more serious and long-term problems in adjustment. Our cluster analytic data support the view that multiple child and family risk , identified in early childhood, is most associated with poor outcomes in middle childhood. Issues to be addressed in the next millennium include biological-genetic factors, neighborhood stresses,


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and cultural factors, as well as continued emphasis on processes linking child behavior, family stress, and negative outcomes. In addition, the extant data underscore the importance of early intervention and prevention using the comprehensive, multisystemic models of Fast Track and MST delivered to toddlers and preschoolers at high risk for externalizing problems.


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Author Notes

Correspondence regarding this article may be addressed to the authors at the Department of Psychology, Clinical Psychology Program, University of Pittsburgh, 4015 O’Hara Street, Pittsburgh, PA 15260 (e-mail: [email protected] or [email protected]). We wish to acknowledge the many staff and graduate students who have worked on our projects over the years and the children, families, and teachers who have participated so willingly. Campbell’s research on hard-to-manage preschoolers was funded by NIMH Grant No. 32735 and Shaw’s research on low income boys was funded by NIMH grant No. 50907.