Copyright 1998 by the American Psychological Association, Inc. I064-1297/98/$3.00
Experimental and C l i n i c a l Psychopharr 1998, Vol. 6, No. 3, 316-324
Effect of Stage of Change on Cue Reactivity in Continuing Smokers Wilson McDermut and David A. F. Haaga American University Three classical conditioning models (the conditioned compensatory response, condilioncd withdrawal, and conditioned appetitive motivational models) postulate that drug cues evoke physiological and emotional responses associated with motivational states that prompt drug use. There is accumulating evidence to suggest that factors other than classical conditioning can influence emotional and physiological reactivity to drug stimuli. This study tested whether stage of change affects the nature of reactivity to smoking cues among continuing smokers. Precontemplators (smokers not considering quitting) and contemplators (smokers considering quitting in the near future) watched videotapes containing smoking cues. Emotional and physiological responses to the smoking video were contrasted with responses to a neutral videotape. Precontemplators had lower heart rates than did contemplators in response to the smoking videotape. Both contemplators and precontemplators evinced increased positive affect in response to the smoking cue. A comparison sample of nonsmokers did not show any reactivity to the smoking cue. Implications of these findings for conditioning theories of smoking are discussed.
ancc. However, conditioned drug-antagonistic responses are unpleasant and are hypothesized to perpetuate a cycle of dependence. For example, a heroin user might experience hyperalgesia (analgesia is an effect of heroin) and chills (heroin increases skin temperature) in the presence of stimuli that have become associated with drag ingestion. As the user repeatedly encounters stimuli that prompt aversive (albeit adaptive) drug-opposite responses, he or she finds that these aversive responses can be relieved by drug use. In addition, drag-opposite responses are posited as the mechanism responsible for relapse. For example, an abstinent addict may experience aversive drag-opposite symptoms on returning to the neighborhood where he or she previously used drugs. The aversive symptoms evoked could precipitate a lapse in an effort to relieve the drug-antagonistic symptoms. The conditioned withdrawal model (Wikler, 1980) provides an alternative account of classical conditioning in cue exposure. On the basis of his clinical work with opiate addicts, Wikler (1980) proposed that physical withdrawal from opiates could be classically conditioned. Clinically, it is not uncommon to hear opiate abusers report that they feel sick (symptoms of opiate withdrawal are similar to symptoms of influenza: runny nose and eyes, diarrhea, muscle aches, and chills) on returning to places where they used to obtain or use opiates (Wikler, 1980). Wikler contended that withdrawal becomes associated with drug use situations and stimuli and can then be elicited by them. Withdrawal becomes conditioned to drug stimuli and situations, Wikler argued, because drug users are often experiencing withdrawal at the time they are using drags (when their last fix is wearing off and signs of physical withdrawal are emerging). Drag-related stimuli then function as conditioned stimuli and eventually trigger conditioned withdrawal responses. According to Wikler (1980), subsequent drug use functions to alleviate withdrawal symptoms elicited by drag-related environments or stimuli.
Addiction theorists have implicated drag-related cues as contributing to ongoing drug use and to relapse after cessation of drug use. According to three classical conditioning models (the conditioned compensatory response, conditioned withdrawal, and conditioned appetitive motivational models), drag cues evoke physiological and emotional responses believed to be associated with motivational states that prompt drug use (Siegel, 1979; Stewart, de Wit, & Eikelboom, 1984; Wikler, 1980). Beyond this general level of agreement, however, conditioning theories make disparate predictions about the nature of the conditioned responses drug cues evoke from drag users (Bradizza, Stasiewicz, & Maisto, 1994). The conditioned compensatory response model proposes that drug cues elicit classically conditioned, drug-opposite physiological and emotional responses (Siegel, 1979). Theoretically, this is an adaptive mechanism, as drag-opposite responses diminish the net effect of the drug, minimizing disruptions in homeostasis and maintaining systemic bal-
Wilson McDermut and David A. F. Haaga, Department of Psychology, American University. Wilson McDermut is now at the Department of Outpatient Psychiatry, Rhode Island Hospital, Providence, Rhode Island. This article is based on a dissertation completed by Wilson McDennut under the supervision of David A. F. Haaga, in partial fulfillment of the requirements for the PhD at American University. The data were presented at the 28th Annual Convention of the Association for Advancement of Behavior Therapy, San Diego, California, November 1994. The research was supported by a University Research Award grant from American University. We thank dissertation committee members Tony Ahrens, James Gray, Tony Riley, and Susan Weiss for their advice and feedback. Correspondence concerning this article should be addressed to David A. F. Haaga, Department of Psychology, Asbury Building, American University, Washington, DC 20016-8062. Electronic mail may be sent to
[email protected].
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STAGE OF CHANGE AND CUE REACTIVITY The conditioned appetitive motivational model (Stewart et al., 1984), on the other hand, emphasizes incentive (appetite-whetting) stimuli as the determinants of motivation to use drugs and subsequent drug taking. Stewart ct al. (1984) suggested that conditioned cues previously associated with the positive affective or reinforcing properties of a drug acquire the ability to innervate the same neural circuitry that the drug itself acts on, thereby increasing positive affect, arousal, and further drag seeking. The appetitive model predicts that exposure to drag-related cues causes increased physiological activation regardless of whether the drug is a stimulant or a depressant (Stewart et al., 1984). This prediction is based on evidence that organisms become tolerant to the depressant effects of drugs and sensitized to the stimulant effects. Thus, after significant experience with a drug, the elicited response is one of excitation, which can be evoked by drug cues. Empirical support for these models varies with the type of drag studied. Animal research, for example, has been equivocal with respect to the compensatory response model, failing to support its predictions regarding compensatory responses to morphine analgesia (Goudie & Demmellweek, 1986) but strongly supporting its predictions about hypothermic effects of depressants (Stewart & Badiani, 1993). A review of psychophysiological studies among humans concluded that alcohol data were mixed: The data generally support the appetitive model, but the conditioned withdrawal model has not been definitively disconfirmcd (Niaura etal, 1988). A growing body of research has also examined conditioned responses to smoking-related stimuli. In a review of research on cue exposure in smokers, Niaura et al. (1988) contended that the empirical data on psychophysiological responses to smoking cues are most consistent with the appetitive model because responses to smoking cues are in the direction of arousal. For example, Saumet and Dittmar (1985) detected striking evidence of finger vasoconstriction among heavy smokers at the sight of a cigarette. Consistent with cue-induced arousal, Abrams, Monti, Carey, Pinto, and Jacobus (1988) and Abrams et al. (1987) observed heart rate increases in smokers presented with smoking cues. For example, Abrams et al. (1988) found that when watching someone light and smoke a cigarette. 12 relapsed smokers showed a pattern of higher heart rate reactivity compared to nonsmokers. Rickard-Figueroa and Zeichner (1985) also observed signs of cardiovascular arousal (blood pressure elevations) in smokers presented with smoking cues. Despite the fact that cue exposure research with smokers generally supports the appetitive model, even this body of data is not without inconsistencies. For example, in a relatively large sample of smokers (n = 48), RickardFigueroa and Zeichner (1985) failed to detect statistically significant increases in heart rate. Indeed, one study found a precipitous cue-induced heart rate deceleration in smokers (Niaura, Abrams, Demuth, Pinto, & Monti, 1989), which is clearly antithetical to the appetitive model. Mood data from studies of cue exposure in smokers also are not consonant with the appetitive model. Contrary to the predictions of the appetitive model, most studies that have assessed mood
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reactivity of smokers to smoking cues have noted increased negative affect, specifically increases in state anxiety (e.g., Abrams et al., 1987, 1988). Payne, Schare, Levis, and Colletti (1991) failed to find evidence of increased positive affect in smokers presented with smoking cues (although they did observe a trend toward increased positive affect). One reason for the lack of consistency in research may be that studies of cue reactivity in smokers have not adequately controlled for stage of change, which might affect responses to drug cues. Stage of change refers to an individual's cognitive, attitudinal, and behavioral orientation toward a problem behavior (Prochaska & DiClcmente, 1983). On the basis of a transtheoretical model of processes of change, Prochaska and DiClemente (1983) outlined live stages of change: 1. Precontemplation: not thinking seriously about change 2. Contemplation: thinking about change 3. Decision making: becoming determined to change; more recently termed preparation (Prochaska, DiClemente, & Norcross, 1992) 4. Action: actively modifying behavior or environment, or both 5. Maintenance: maintaining new behaviors. Individual differences in stage of change may affect the nature of reactivity to smoking cues. For example, Abrams et al. (1988) found that when watching someone light and smoke a cigarette, recently relapsed smokers (presumably a mix of precontemplators and contemplators) showed higher heart rate reactivity compared with nonsmokers than did quitters (participants in the action or maintenance phases). Thus, heart rate reactivity apparently differed by stage of change. Samples of smokers in cue exposure studies are typically heterogeneous with respect to stages of change, which might explain inconsistencies in the cue exposure literature. For example, Rickard-Figueroa and Zeichner (1985) found only nonsignificant elevations in heart rate in smokers exposed to smoking cues. As this sample was composed of participants whose stage of change is unknown, we do not know if contemplators and precontemplators had opposing reactions, cancelling each other out. Furthermore, the emotional reactivity data contradicting the appetitive motivation model (i.e., evidence of cue-induced anxiety and failures to find increased positive affect) may stem from the presence of a majority of contemplators, who are, in principle, conflicted about their smoking and may find cue exposure studies to be aversive. This study examined the effect of stage of change on cue-induced emotional and physiological responses in a sample of continuing smokers. More specifically, we compared precontemplators and contemplators. We anticipated that continuing users who are contemplating quitting might experience negative affective responses to smoking cues. According to Prochaska and DiClemente (1983), smokers actively considering quitting (contemplators) reported feeling and thinking more about themselves in relation to their problem behavior and perhaps "become upset enough with themselves and their smoking to make commitments to quit" (p. 394). In contrast, precontemplators, those not currently
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considering quitting smoking, "spend less time reevaluating themselves as smokers" and "experience fewer emotional reactions to the negative aspects of smoking" (Prochaska & DiClemente, 1983, p. 393). We also evaluated whether contemplators and precontemplators could be differentiated on the basis of their physiological responses to smoking cues, although stages of change theory makes no specific prediction about the direction of such changes. To detect any possible unconditioned effects of these stimuli that could confound the interpretation of the main results, we used the same stimuli to test a comparison group of never-smokers.
Method Participants Ninety daily smokers were recruited through newspaper advertisements, fliers placed around the American University campus, and word of mouth. They were paid $10 each for their participation. Students taking psychology classes were given the choice of $ 10 or credit in their psychology class. Three smokers chose course credit. The smokers averaged 24.7 years of age (SD — 8.6), and 68% were women. Of the smokers, 73% were Caucasian, 20% African American, 4% Asian, and 2% other minorities. Our sample of smokers reported smoking an average of 16.2 (SD = 8.5) cigarettes per day and having smoked for an average of 8.0 (SD = 8.0) years, with an average of 2.7 (SD = 2.8) past attempts to quit smoking. Their mean score on the Fagerslrom Test for Nicotine Dependence (Heatherton, Kozlowski, Frecker, & Fagerstrom, 1991) was 2.9 (SO = 2.2), and 90% (« = 81) of them met Diagnostic and Statistical Manual of Mental Disorders (3rd ed., rev.; DSM-IU-R; American Psychiatric Association, 1987) criteria for nicotine dependence. The comparison group of never-smokers were 27 undergraduate psychology students who were offered class credit in exchange for their participation. This group was 81 % female and had a mean age of 19.8 years (SD = 4.1). The majority (81%) were Caucasian, with 8% African American, 4% Hispanic, and 8% Asian. To participate in the study, nonsmokers had to report having smoked fewer than 5 cigarettes in their lifetime.
Measures DSM—III-R nicotine dependence diagnoses were made on the basis of responses to tobacco use questions from the Substance Abuse Module (SAM; Robins, Cottier, & Babor, 1990) of the Composite International Diagnostic Interview, Core Version 1.0 (CIDI; World Health Organization [WHO], 1987). The CIDT is a standardized diagnostic interview to facilitate classification of psychiatric disorders according to DSM—III-R and International Classification of Diseases, Version 10 (ICD-10; WHO, 1989) criteria. Interrater reliability of both CIDI-SAM diagnoses (kappa values over .93) and individual items (kappa values over .94) has been found to be excellent (Cottier ct al., 1991). Among smokers only, severity of nicotine addiction was measured with the Fagerstrom Test for Nicotine Dependence (FTND; Heatherton et al., 1991), a revision of the Fagerstrom Tolerance Questionnaire (FTQ). Favorable validity data have been obtained for the FTQ (Fagerstrom & Schneider, 1989). Its revision was prompted by low internal consistency. Relative to the FTQ, the FTND has shown higher internal consistency (Heatherton et al.,
1991) and a significantly higher correlation with expired air carbon monoxide level (Scidncr, Burling, Gaither, & Salvio. 1994). Positive and negative affect were measured by the state ("at this moment") version of the Positive and Negative Affect Schedule (PANAS; Watson, Clark, & Tellegen, 1988). The PANAS consists of Iwo sets of 10 adjectives, one set measuring positive affect, the other negative affect. Each affect item is rated from 1 to 5. The range for each subscale is thus 10 to 50, with higher scores reflecting more intense affect. The Negative and Positive subscales have been found to he only minimally intercorrelated (r = -. 15 for the state version; Watson et al., 1988). Among smokers only, subjective craving was assessed by a visual analogue, dotted line rating scale ranging from 0 (no craving) to 100 (intense craving), with every dot representing a 2-point increment in craving and with intervals of 10 indicated numerically. Heart rate and skin temperature were measured continuously during neutral and smoking videotapes, using Lafayette Instrument Company monitors (Lafayette, IN). The number of heart beats per minute was calculated every 5 s by the heart rate monitor and transmitted to and stored in a receiving device. Skin temperature was displayed digitally on the skin temperature monitor. While participants watched the videotape, the experimenter recorded their skin temperature by hand on paper every 15 s. Eight smokers and four never-smoking comparison participants were excluded from heart rate analyses because of equipment failure. One smoker and one nonsmoker were dropped from skin temperature analyses because of measurement artifacts such as touching the skin temperature probe to another part of the body. Contemplation of smoking cessation (among smokers only) was measured in two ways. Group classification was determined by asking, "Do you intend to quit smoking in the next 6 months?" (cf. DiClemente et al.. 1991). Those responding "yes" were classified as contemplators, whereas those responding "no" were classified as precontemplators. Groups categorized in such a way have, in past research, differed significantly in self-efficacy, evaluation of the pros and cons of smoking, and subsequent quitting behavior (Prochaska & DiClemente, 1992). The second measure was a continuous variable, the Contemplation Ladder (CL; Biencr & Abrams, 1991). The CL consists of a ladder with 10 nings labeled 1 to 10. The lowest score, 0, represents no thought of quitting. The highest rung, 10, represents taking action to quit (e.g., cutting down, enrolling in a program). In a worksite sample of smokers, CL scores predicted subsequent attendance at an educational program about smoking and associated risks (Biener & Abrams, 1991).
Stimuli Each videotape was 4 min long. The neutral videotape consisted of an actress placing a call to a friend and then talking with the friend about routine plans for socializing. The smoking-reiated video consisted of the same actress smoking a cigarette while talking on the phone and making plans with a friend. The affective valence of the situalions depicted in each videotape is neutral, and the actress's affect is neutral throughout each videotape. During the smoking videotape, the pack of cigarettes becomes visible 7 s into the videotape. She lights the cigarette at 40 s and takes the first puff 45 s into the videotape. As a manipulation check, immediately after presentation of the smoking video, participants who smoke were asked to rate on a l-to-10 scale how similar the situation in the video was to situations in which they sometimes smoke. The mean, median, and modal response was 7, between the verbal anchors somewhat similar (5-6) and exactly the same (10), suggesting that the video
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STAGE OF CHANGE AND CUE REACTIVITY was. on average, realistic and personally relevant and, by extension, capable of evoking conditioned responses.
Procedure After telephone screening and appointment scheduling, participants were asked not to smoke for 2 hours before the study. In the laboratory session, after obtaining informed consent, the interviewer (the first author) administered the CIDI-SAM diagnostic interview.1 Next, participants were asked to wear the heart rate monitor and skin temperature probe, which was attached with surgical tape to the palmar surface of the middle finger of the nondominant hand. The initial interview and preparations for viewing the videotape took approximately 20-25 min. The participant was seated in front of a television and videocassette player. Videotapes were presented in random order. After each videotape, mood measures were completed, and for smokers the craving measure. Finally, smokers completed the contemplation measures and the FTND. Contemplation measures and the FTND were completed at the end of the study in the hope of minimizing the extent to which responding to these measures might serve as smoking-related cues for some smokers, thus obscuring the impact of the videotaped stimuli themselves.
Data Reduction The actress in the video did not begin smoking the cigarette until 45 s into the video. As such, only heart rate and skin temperature data collected during the last 3 min and 15 seconds of the smoking and neutral videotapes were included in data analyses. This procedure yielded 40 heart rate measurements (every 5 s) per videotape for each participant. The 40 heart rate measurements were then reduced to one overall mean for each video. This overall mean was used in data analyses. Skin temperature was recorded every 15s; thus, 14 skin temperature measurements were available per video for each participant. These skin temperature measurements were also reduced to one overall mean per video.
Results Data-Analytic Plan An alpha level of .05 (two-tailed) was used for all inferential statistical tests. PANAS Negative Affect subscale scores were negatively skewed. We performed a logarithmic transformation on this variable, which reduced negative skew from 1.2 to 0.57 for neutral video scores and from 1.5 to 0.51 for smoking video scores. Parametric analyses used the log-transformed negative affect variable (Bordens & Abbott, 1988). Skin temperature was positively skewed. We attempted a power transformation to pull in the left tail of the distribution, as recommended by Fox (1991), but this transformation was unsuccessful at correcting the skew. Therefore, analyses of skin temperature data used nonparametric techniques. Results arc presented in four parts. First, to determine whether unconditioned effects of the cues could complicate interpretation of our major findings, we analyzed the responses of never-smokers to the smoking versus neutral videos. Second, to address the overall impact of the smoking cue, without regard to contemplation status, we report paired t tests comparing neutral video with smoking video re-
sponses for all smokers as a group. Third, our major analyses, of the effect of stage of change on mood, craving, and physiological reactivity, are analyses of covariance (ANCOVA) in which response to the smoking cue was the dependent variable, with contemplation status as the independent variable and response to the neutral cue as the covariate. Fourth and finally, we report secondary analyses of order effects, of the relation of stage of change to specific-mood (as opposed to summed scores for Positive Affect and Negative Affect) cue reactivity and of the relation of severity of nicotine dependence to cue reactivity. In all cases in which ANCOVAs are reported, the assumption of homogeneity of regressions was met.
Unconditioned Effects
of Smoking Cue
Never-smokers showed no significant responsiveness to the videotaped smoking cue. Their state Negative Affect scores (PANAS) were the same, on average, after the smoking video (M — 13.8, SD = 4.4) as after the neutral video (M = 13.8, SD = 4.0), and state Positive Affect was nearly identical as well (smoking video M = 19.6, SD = 6.4; neutral video M = 19.5, SD = 7.1). Likewise, their average heart rate during the smoking video (M = 78.1, SD = 6.8) was not significantly different from the average heart rate during the neutral video (M = 78.6, SD = 6.6), as was their skin temperature (smoking video M = 9\.5, SD = 5.0; neutral video M = 92.0, SD = 3.3). Thus, our comparison group of never-smokers showed little reactivity to the videotaped smoking cue, which bolsters the inference that any effects shown by our main sample of smokers are attributable to their conditioning histories with cigarette smoking.
Cue Reactivity of Smokers Overall reactivity of all smokers to the smoking cue was assessed by paired (tests to compare smokers' responses to the smoking cue with their responses to the neutral cue on the five dependent variables (positive affect, negative affect, craving, heart rate, and skin temperature). Compared to the neutral cue (M = 18.9, SD = 7.4), smokers showed significantly higher positive affect in response to the smoking video (M = 21.5, SD = 7.6), f(89) = 4.03, p < .0001. In a similar manner, smokers reported higher levels of craving (M = 58.7, SD = 25.2) after the smoking video, relative to the neutral video (M = 51.2, SD = 27.4), r(88) = 4.02,p < .0001. Smokers' average heart rates during the smoking 1 As part of the C1D1-SAM interview, participants were asked when they had smoked their last cigarette. On average, they reported that it had been 6.3 hr since their last cigarette (SD = 5.9), suggesting that smokers went beyond compliance with the request that they avoid smoking within 2 hr of the study and perhaps calling into question the degree of nicotine dependence characterizing our sample. However, this figure is inflated considerably by the fact that about 28% of our participants went through our study protocol early in the morning before they had had their first cigarette. Thus, the period of abstinence was longer than required because we counted the time they were asleep as time without a cigarette.
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video were significantly lower (M = 74.9, SD = 11.0) than during the neutral video (M = 75.5, SD = 10.9), ((81) = -2.25, p < . 05. Conversely, smokers' skin temperatures were essentially unchanged in response to the smoking cue. Their mean skin temperature was 92.1 °F (SD = 4.1) during the neutral video and 92.0 (SD - 4.2) during the smoking video. A Wilcoxon matched-pairs signed-ranks test revealed that this difference was not significant. Log-transformed Negative Affect scores also did not differ significantly in response to the neutral (raw M = 15.1, SD = 4.8) versus smoking (raw M = 15.8, SD = 5.3) videos.
Contemplators Versus Precontemplatnrs Demographics and smoking history. Fifty-six smokers were classified as preconlemplators, and 31 as contcmplators. In support of the convergent validity of the 1-item measure used to determine stage of change, contemplators' mean score of 7.3 (SD = 1.7) on the Contemplation Ladder was significantly higher than the mean of 4.3 (SD = 2.1) obtained by precontemplators, r(85) = 6.81, p < .0001. Sixty-eight percent of precontemplators and contemplators were women. The average age of precontemplators (M ~ 23.5, SD = 7.9) did not differ significantly from that of contemplators (M = 25.7, SD = 9.0). Eighty percent of precontemplators were Caucasian, which did not differ significantly from the proportion (65%) among contemplators. Precontemplators reported having smoked an average of 16.8 cigarettes (SD - 8.3) per day for an average of 7.3 years (SD - 7.5). Contemplators smoked an average of 14.2 cigarettes (SD — 8.3) per day for an average of 8.3 years (SD — 8.3). Precontemplators obtained an average score on the FTND of 2.95 (SD - 2.2) and contemplators obtained an average of 2.45 (SD = 2.1). A multivariate analysis of variance comparing precontemplators and contemplators on the measures of smoking history and level of nicotine dependence (years smoking, cigarettes per day, FTND score) was not significant. Cue reactivity. Table 1 lists means for contemplators and precontemplators on each dependent variable. Except in the case of skin temperature, ANCOVAs were conducted to determine whether or not contemplators and precontemplators showed differential reactivity to the smoking videotape while controlling for their reactivity in response to the neutral videotape. ANCOVAs revealed that contemplation status did not significantly predict Positive Affect, Negative Affect, or craving. In the case of skin temperature, MannWhitney U tests showed that contemplators and precontemplators did not have different skin temperature in response to either the neutral video or the smoking video. Wilcoxon matched-pairs signed-ranks tests were used to determine if precontemplators or contemplators showed within-groups skin temperature reactivity to the smoking video relative to the neutral video. Neither precontemplators nor contemplators had significantly different mean skin temperatures during the smoking video as compared with the neutral video.
Table 1 Mean Affect, Craving, and Physiologic Scores for Precontemplators and Contemplators Neutral video
n
M
56 31
18.4 18.8
7.6 6.7
20.7 22.5
7.7 7.4
56 31
15.3 14.7
4.7 4.6
15.6 16.1
5.2 5.5
55 31
49.8 51.2
28.5 25.2
58.0 58.6
26.0 24.7
50 29
75 2 75.7
10.8 11.5
74.1 76.3
10.6 11.7
55 31
91.7 92.8
4.6 2.9
91,5 92.9
4.8 3.0
Variable Positive affect Prccontcmplators Contemplators Negative affect Precontemplators Contemplators Craving Precontemplators Conlemplalors Heart rate Precontemplators Contemplators Skin temperature Precontemplators Contemplators
Smoking video
SD
M
SD
Note. Positive and negative affect were measured by positive and negative subscales of the Positive and Negative Affect Schedule. Craving was measured with a 100-point Visual Analogue scale.
Inspection of means in Table 1 shows that precontemplators' mean heart rates decreased during the smoking video relative to the neutral video, whereas contemplators' mean heart rates increased during the smoking video relative to the neutral video. An ANCOVA revealed that contemplation status was a significant predictor of heart rate during the smoking video while controlling for heart rate during the neutral video, F(l, 76) = 9.6, p < .005, indicating that, relative to conlemplators, precontemplalors' heart rates were significantly lower during cue exposure.2
Secondary Analyses Stage of change and specific PANAS items. The Positive Affect and Negative Affect subscales of the PANAS contain items reflecting a diverse array of moods. For example, the Positive Affect subscale of the PANAS is composed of items such as attentive, determined, proud, strong, and excited, and the Negative Affect subscale is composed of afraid, ashamed, hostile, jittery, and upset, among others. This raises the possibility that overall PANAS subscale scores might obscure important differences between contemplators and precontemplators on specific affects.
2 We also used the Contemplation Ladder variable as a potential predictor of cue reactivity. We performed four separate multiple regression analyses in an attempt to predict cue reactivity on the basis of the ladder variable. While controlling for reactivity to the neutral video, the ladder variable was not a significant predictor of craving, positive or negative affect, or heart rate. A nonparametric partial correlation between the ladder variable and skin temperature during the smoking video (while controlling for skin temperature during the neutral video) was also not significant. Thus, the dichotomous measure of contemplation status was a better predictor of cue reactivity than the continuous measure.
STAGE OF CHANGE AND CUE REACTIVITY To explore this possibility, we conducted ANCOVAs with each PANAS item after the smoking video as the dependent variable, the corresponding item score after the neutral video as the covariate, and stage of change as the independent variable. Stage of change was a significant predictor in three of these analyses. Specifically, contemplators were significantly more likely to react to the smoking video with increases in feeling guilty, F(\, 84) = 4.23, p < .05, and strong, F(\, 84) = 5.24,p < .03, and significantly less likely to report increases mafraid F(\, 84) = 4.14,p < .05. These item analyses must be considered as very tentative. They were not based on specific theory-driven predictions, and none of them would be considered significant if one applied a Bonferroni correction to the comparisonwise alpha levels to account for multiple inferential tests. They are reported here and discussed solely as possible leads for future research rather than as definitive findings. Nicotine dependence and cue reactivity. We examined the degree to which severity of nicotine dependence influenced the nature of cue reactivity. With FTND score as the independent variable, we conducted a series of multiple regression analyses predicting scores on the dependent measures during the smoking video while controlling for scores on the dependent measures during the neutral video. We performed four regression analyses. Score on the FTND, our measure of nicotine dependence, was not a significant predictor of positive or negative affect, heart rate, or craving. In the case of skin temperature (which was not normally distributed), we calculated nonparametric partial correlations based on Kendall's tau (Gibbons, 1993). The nonparametric partial correlation between skin temperature and FTND also was not significant. Order effects. Finally, to determine whether order of video presentation influenced reactivity, we performed five separate, mixed Within (neutral vs. smoking video) X Between (neutral-first vs. smoking-first order) ANOVAs, with Positive Affect, Negative Affect, craving, skin temperature, and heart rate as dependent measures. There was one significant interaction between order and type of video, with Positive Affect as the dependent variable. Smokers who saw the neutral video first obtained a mean PANAS Positive Affect score of 18.8 (SO = 1.2) after the neutral video, nearly the same as after the smoking video (M = 19.0, SD = 6.5). Conversely, those who saw the smoking video first scored higher in Positive Affect after the smoking video (M = 24.0, SD = 7.8) than after the neutral video (M =19.0, SD = 7.7). Thus, the effect of the cue on positive affect was stronger when the smoking video was presented first.
Discussion Continuing smokers watched two similar brief videotapes, one of which included a smoking cue. They reported state positive and negative affect, as well as craving for a cigarette, after each video. Heart rate and skin temperature were monitored during the videos as well. A comparison sample of never-smokers showed no significant emotional or physiological reactivity to the smoking cue, supporting the inference that the smokers' responses reflect conditioning.
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Smokers as a group showed significantly higher positive affect, more intense craving, and lower heart rates in response to the smoking cue. Taken together with participants' fairly high ratings (average of 7 on a 1-10 scale) of the similarity of the videotaped smoking scenario to situations in which they smoke, these significant effects suggest that the smoking video presented a realistic and meaningful cue. It should be noted that, although heart rate was slower during the smoking video than during the neutral video (Ms = 74.9 and 75.5, respectively), the difference was small. This finding should be replicated by other researchers before it can be interpreted as an unequivocal sign of cue reactivity. Our finding of higher positive affect in response to the smoking cue is consistent with the conditioned appetitive motivational model, which posits that conditioned cues previously associated with the positive affective or reinforcing properties of a drug acquire the ability to innervate the same neural circuitry that the drug itself acts on, thereby increasing positive affect. Nicotine has multiple sites of action in the brain, but its ability to increase brain activity of dopamine, norepinephrine, and beta-endorphin is thought to mediate its euphoriant effects (Carmody, 1989). According to the appetitive model, the repeated association between smoking cues and nicotine's euphoriant effects would eventually result in the ability of the cues themselves to evoke positive affect. Only one other study (Payne et al., 1991), to our knowledge, has measured the effect of smoking cue exposure on positive affect. Payne et al., however, found only a nonsignificant trend toward increased Positive Affect. Accordingly, replication of our results would be important before placing high confidence in this effect. If corroborated, the increase in Positive Affect has important implications for future research and theorizing. First, future research should test whether the positive affect induced by cue exposure is indeed the product of conditioning that allows cues to stimulate the same area of the brain in which drugs work. Functional brain imaging techniques (e.g., positron emission tomography) could be used to address this issue. Smokers could be scanned during nicotine infusion and again during exposure to nicotine cues. The appetitive model predicts that the brain scans in these two conditions would be virtually identical. Second, our Positive Affect findings are relevant to other ongoing theory and research that attempt to explain the relations among cue exposure, mood, and subsequent substance use. In particular, any theory that attempts to explain the relation between cue exposure and drug use should not rely exclusively on the role of negative affect. For example, Stasiewicz and Maisto (1993) have extended Mowrer's (1947) two-factor theory of avoidance learning to substance use disorders, stating that "the two-factor model predicts an increase in negative affect and the emergence of aversive stimuli (e.g., thoughts, images, memories) following exposure to drug-related stimuli" (p. 346). Our results suggest that theories that address the affective consequences of cue exposure should attempt to delineate the conditions under which positive versus negative affect will be induced. Several studies with people dependent on heroin or alcohol
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and in the early stages of treatment have found that cue exposure increases negative affect (e.g., Cooney, Gillespie, Baker, & Kaplan, 1987; Powell, Bradley, & Gray, 1992). The contrast between our findings and those of studies involving individuals in treatment or people addicted to drugs with more severe short-term negative consequences suggests that continuing users of legal and nonintoxicating (i.e., caffeine and nicotine) drugs might be the most likely to show positive affect during cue exposure. Positive affect reactivity to the smoking cue was qualified by an order effect, in that positive affect was substantially higher after the smoking video only if it was presented first. Some participants commented that watching two fairly similar videos in the same session was boring, and it is possible that boredom offset a Positive Affect-enhancing effect of the smoking cue if the smoking video was presented after the neutral video. The only other tobacco cue exposure study we are aware of that reported order effects noted a carryover effect for craving. Craving tended to continue increasing over time, regardless of order of cue presentation (Rickard-Figueroa & Zeichncr, 1985). These results suggest that researchers should be alert to the impact of order effects on cue reactivity.
Stage of Change and Reactivity Whereas increased Positive Affect in response to the smoking cue supported the conditioned appetitive model, heart rate decreases are contradictory to that model and instead support conditioned compensatory response (nicotine accelerates heart rate) or conditioned withdrawal (bradycardia is a symptom of nicotine withdrawal) models. Thus, our study is similar to previous research, noted in the Introduction, in obtaining mixed results with respect to conditioning models. Part of the rationale for this investigation was that these equivocal results might be illuminated by focusing on the relation of individual differences in stage of change and cue reactivity. We had anticipated that smokers contemplating quitting in the near future (contemplators) might experience more Negative Affect in response to smoking cues than would smokers not thinking about quitting (precontemplators). Although the mean scores were in this direction, there was no significant effect of contemplation status on Negative Affect reactivity. Contemplators and precontemplators alike reported increased positive affect after the smoking cue, which may have practical implications. It is perhaps not surprising that precontemplators would show this effect. However, it is surprising that contemplators would react with increased positive affect, given that an implicit facet of contemplation is the notion that smoking is undesirable. Contemplators should perhaps be informed that one of the potential reactions to exposure to cues is positive affect, in the hope of normalizing this reaction. Otherwise, for a contemplator, such an effect may seem paradoxical and could induce a state of cognitive dissonance that the individual might attenuate by reconceptualizing himself or herself as not ready to quit (e.g., "I feel excited when I see other people smoking. I guess I am very addicted and not ready to quit.").
The secondary analysis suggesting that contemplators felt more guilty in reaction to the smoking cue than did precontemplators is consistent with this scenario. Treatment implications of the findings must be considered as tentative, however, in that our study is correlational and cross-sectional as it relates to stages of change, despite the within-individuals manipulation of videotaped cues. We cannot say, for instance, whether contemplators' feelings of guilt (if robust) during cue exposure are an impediment to further progress toward smoking cessation or instead a direct cause of the movement from precontemplation to contemplation, suggesting the possibility of guilt induction as an intervention in hastening the attitude changes and consciousness raising that is considered especially useful at early stages of change (Perz, DiClemente, & Carbonari, 1996). The main difference between precontemplators and contemplators was that precontemplators showed significantly lower heart rate during the smoking video (controlling for neutral video heart rate) than did the contemplators. This effect cannot be attributed to extent of smoking history or level of nicotine dependence, as stage of change was not significantly related to these variables, nor to demographics. The difference in heart rate reactivity between precontemplators and contemplators supports the view that these are distinct stages of change and that stage of change should be taken into account in cue exposure research. Our findings are consistent with the results of another cue exposure study with smokers that found that smokers in different stages of change exhibited differential cue-induced reactivity (Abrams et al., 1988). Contemplators may have been girding themselves psychologically against their increased craving. Perhaps they initiated some cognitive coping tactic, which Baker, Cannon, Tiffany, and Gino (1984) hypothesized is associated with cardiac acceleration. The secondary analysis indicating that contemplators endorsed feeling "strong" to a greater extent after the smoking cue than did precontemplators is consistent with this possibility. This conjecture could be tested in future research using laboratory analogue measures of smokers' cognitive responses to smoking cues (Drobes, Meier, & Tiffany, 1994; Haaga, 1989).
Methodological Limitations Methodological limitations of this study suggest cautious interpretation of the findings. First, our participants smoked less than the typical American smoker. For example, 27% of American smokers smoke 25 or more cigarettes per day (U.S. Department of Health and Human Services, 1990), compared to 12% of our sample of smokers. Some of our participants may have had an insufficient conditioning history with nicotine, which could explain small effects (e.g., heart rate) or the lack of effect on skin temperature. Second, affect and craving were measured only after each video, whereas heart rate and skin temperature were monitored during each video. If there were, for instance, immediate but transient increases in negative affect at the beginning of the smoking videotape (consistent with the compensatory response and conditioned withdrawal models), these effects would not be captured by our measurement procedures.
STAGE OF CHANGE AND CUE REACTIVITY Third, we could not confirm that participants were actually abstinent for at leasl 2 hr before the study. We know for certain only that they were abstinent for approximately the first 20-25 min of the protocol. Fourth, participants in this study represented only two of the five stages of changes. Further research in this area should attempt to compare all five groups in terms of their reactivity to smoking cues. Finally, this group of smokers is relatively young and contained a small number of contcmplators, detracting from statistical power. A replication with older, more veteran smokers and a larger sample would be valuable.
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Received June 4, 1997 Revision received November 18, 1997 Accepted March 10, 1998 •
