Blackwell Publishing AsiaMelbourne, AustraliaPCNPsychiatry and Clinical Neurosciences1323-13162006 Folia Publishing SocietyApril 2006602160167Original ArticleCorrelates of methamphetamine useC-F. Yen et al.
Psychiatry and Clinical Neurosciences (2006), 60, 160–167
Regular Article
Correlates of methamphetamine use for Taiwanese adolescents CHENG-FANG YEN, md, phd,1 YI-HSIN YANG, phd2 AND MIAN-YOON CHONG, md, phd, frcpsych3,4 1
Department of Psychiatry and Graduate Institute of Behavioral Science, 2Statistical Analysis Laboratory, Department of Clinical Research and Graduate Institute of Oral Health Sciences, Kaohsiung Medical University, 3Department of Psychiatry, Chang Gung Memorial Hospital, Kaohsiung, and 4Department of Psychiatry, Chang Gung University, Taipei County, Taiwan
Abstract
The aim of the present study was to assess the associations between methamphetamine (MAP) use and psychiatric comorbidity, individual attitudes and personal knowledge of MAP use, family characteristics and peer factors in Taiwanese adolescents via a case–control study. Two hundred adolescent MAP users and 400 adolescent non-users were recruited. Their psychiatric comorbidity, attitudes and knowledge toward MAP use, family characteristics and peer interactions were assessed systematically. The associations between MAP use and those factors were examined by univariate and multivariate analysis. In conditional logistic regression analysis, comorbid conduct disorder, attitude favorable to MAP use and poor knowledge of MAP use, disrupted parenting, lower caregiver education level, having friends using or providing MAP and actively interacting with peers were associated significantly with MAP use. Adolescent MAP use was correlated with multiple factors that lie within individuals and the interaction with their family and peers. Correlates of MAP use identified in the present study may be helpful for the design and implementation of preventive intervention.
Key words
adolescents, comorbidity, family relations, methamphetamine, peer relations.
INTRODUCTION Methamphetamine (MAP) use has become a major public health issue in the Asia–Pacific region.1 Methamphetamine use in Taiwan has also been increasing since the end of the 1980s. Both government criminal statistics and a national trends survey demonstrate that MAP use among adolescents has become an important social issue in Taiwan.2,3 In a study of adolescent vocational students in southern Taiwan, 4.9% of the subjects reported previous use of MAP.4 In Taiwan MAP is known colloquially as ‘sugar’ (for the form of powder or crystal) or ‘AN’ (abbreviation of amphetamine). Methamphetamine users inhale the fumes produced
Correspondence address: Mian-Yoon Chong, MD, PhD, FRCPsych, Department of Psychiatry, Chang Gung Memorial Hospital, 123, Ta-Pei Road, Niao-Sung Hsiang, Kaohsiung County 83342, Taiwan. Email:
[email protected] Received 7 March 2005; revised 31 August 2005; accepted 25 September 2005.
when powdered MAP is heated in a glass pipe or empty light bulb. Because MAP is a stimulant that acts on the central nervous system, misuse can result in serious physical, psychological and social consequences,5 including MAP psychosis.6 The government has therefore directed a number of resources to prevent initial and habitual use of MAP and to investigate high-risk situations for MAP use in Taiwan. The most promising route for development of effective strategies for the prevention of adolescent substance abuse involves a risk-focused approach, which requires the identification of risk factors for drug use.7 These risk factors include individual determinants and their respective interpersonal environments. Of the individual risk factors, psychiatric comorbidity has been considered one of the most important.8,9 Conduct disorder, attention deficit/hyperactivity disorder (ADHD) and mood disorder are the three most commonly investigated comorbidities.10–14 However, the prevalence of comorbidities and their effect on MAP use in adolescents needs further examination. Attitude
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toward drug use has been considered one of the individual determinants of drug use. Kandel et al. have indicated that attitudes favorable to use of a drug increase the risk of its subsequent abuse.15 Family and peer group are important environmental factors affecting adolescent drug use.7 Of the principal family characteristics, drug-related behavior,16,17 parental divorce,18 low parental education level,19 high family conflict,20 impoverished intrafamilial bonding14,20 and low family monitoring21 have been associated with substance use. However, studies of family influence on MAP use are very rare, in comparison to analogous investigations that have focused on family influence on alcohol, cigarette smoking, and marijuana use. Of the peer-group factors, affiliation with peers abusing substances22 and engaging in delinquent behaviors,20 peer pressure to take drugs23 and peer rejection24 are the most commonly investigated factors associated with substance use. The correlates of MAP use have seldom been investigated in adolescents, however.25 The aim of the present study was to assess the associations between MAP use and psychiatric comorbidity, individual attitudes and personal knowledge with respect to MAP use, family characteristics and peer factors in Taiwanese adolescents via a case–control study. Because age and gender have been identified as the most consistent demographic predictors for drug use,26 the subjects in the index and control groups were matched according to age and gender, and conditional logistic regression was performed for statistical analysis.
MAP use proved for all based on a positive urine test. Mean age was 17.0 ± 1.0 years (range, 15–19 years), and average duration of education was 8.3 ± 1.3 years. Eighty-four of the subjects (42%) had their first MAPuse experience before 16 years of age, while 80 (40%) had used MAP more than four times per month. A total of 400 age-matched (mean age ± SD, 17.0 ± 0.9 years; range, 15–19 years) and gendermatched adolescents (250 male and 150 female) were randomly selected from two senior high schools (n = 200) and three vocational schools (n = 200) as controls. All subjects in the control group reported that they had never used MAP, with this fact confirmed by their teachers. Their mean educational level was 10.9 ± 0.9 years (range, 9.5–11.5 years).
METHODS
The Questionnaire for Attitude and Knowledge of Methamphetamine Use (QAKM(, with subscales for attitude and knowledge with respect to MAP use, was modified from the questionnaire originally developed by Lee.30 The attitude subscale contained 25 four-point items that assessed the attitudes of subjects toward MAP use, with a Cronbach’s alpha of 0.85. The knowledge subscale contained 33 items that tested understanding of MAP use, with a Cronbach’s alpha of 0.87. Because attitude to drug use was correlated with knowledge with respect to its consequences (Pearson correlation = 0.347; P < 0.001), the scores for the attitude and knowledge subscales were averaged. Higher average attitude–knowledge scores indicated that the subjects had an attitude favoring MAP use and poor knowledge of its consequences.
Sample According to Taiwan’s juvenile act, adolescents who are arrested for the use of illicit drugs are required to undergo a detoxification program at a detention center for 3–4 weeks. The Ministry of Justice encourages psychiatrists to approach all juvenile drug offenders to gather information about the associated psychological, behavioral and familial dimensions to determine the risk of relapse and to intervene in the management of deviant behavior where appropriate. In the present study, adolescent MAP users (index group) were recruited consecutively from two juvenile detention centers in Taiwan from September 1999 to March 2002. Those who refused an interview (n = 6), could not understand the contents of interviews due to belowaverage mental function (n = 2) and those unable to complete all assessments at discharge (n = 6) were excluded. Two hundred adolescent detainees (125 male and 75 female) were assessed during this period, with
Assessment Epidemiological version of the Kiddie Schedule for Affective Disorders and Schizophrenia A child psychiatrist conducted the diagnostic interview using Kiddie Schedule for Affective Disorders and Schizophrenia (K-SADS-E) to test for lifetime psychiatric morbidity.27 The instrument has been modified for use in the Taiwanese population, with colloquial expressions adapted for many items.28 Diagnoses of lifetime psychopathology were made according to the operational criteria of DSM-IV.29
Questionnaire for Attitude and Knowledge of Methamphetamine Use
Adolescent Family Life Questionnaire The Adolescent Family Life Questionnaire (AFLQ) consisted of three four-point family subscales: conflict,
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monitoring and support, with Cronbach’s alpha ranging from 0.73 to 0.81. Higher scores on the AFLQ indicate a lower level of family conflict, and increased family monitoring and support. The AFLQ also assessed drug use among the parents and siblings of subjects.
Adolescent Social Life Questionnaire The Adolescent Social Life Questionnaire (ASLQ) consisted of five subscales: rank within and subjective perception with respect to the peer group; active interaction with peers; self-efficacy to resist peer pressure; peer delinquent behavior; and involvement in social activities that increase the risk of MAP use, with Cronbach’s alpha ranging from 0.68 to 0.85. Higher scores on the ASLQ indicate higher rank within and increased satisfaction with status in peer group, more active interaction with peers, higher self-efficacy to resist peer pressure, less peers with delinquent behavior, and less involvement in social activities that increase the risk of MAP use. The ASLQ also assessed drug use among the subject’s friends. Questionnaires were developed to ascertain the salient sociodemographic factors, including sex, age, education, caregiver education (0, never received formal education; 1, primary school; 2, junior high school; 3, senior high school; 4, college; 5, master degree; 6, PhD degree), parents’ marital status (having disruptive parenting or not), and the total number of siblings. We also assessed the characteristics of MAP use for subjects in the index group, including age at first exposure, average expenditure and frequency of use.
Procedure Written informed consent was obtained from all subjects prior to study commencement. Owing to the low literacy of the subjects in the index group, social workers and research assistants read all questions to the subjects face to face to maximize comprehension and reliability. In contrast, the control group completed all questionnaires based on the explanations of the research assistants and under their direction. During this period, a child psychiatrist conducted K-SADS-Ebased diagnostic interviews for all subjects to determine lifetime psychiatric morbidity based on DSM-IV.
Statistical analysis The case–control method of analysis was applied. Odds ratio (OR) with 95% confidence interval (CI), χ2 test, Fisher’s exact test and t-test were used to validate the associations between MAP use, lifetime psychiatric
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comorbidity, attitude and knowledge with respect to the drug use, familial characteristics, and peer factors. Significant factors from univariate tests were selected for further regression analysis. Because the case and control groups were matched on gender and age, conditional logistic regression with stepwise selection (probability of stay = 0.05) was used to identify the important factors for MAP use while considering the matched design.31 The conditional logistic regression analysis was carried out using stata 6.0 windows statistical software (StataCorp, College Station, TX, USA). P < 0.05 was considered statistically significant.
RESULTS Psychiatric comorbidity The relationship between lifetime psychiatric comorbidity and MAP use for the index and control groups is detailed in Table 1. Conduct disorder, ADHD and adjustment disorder were significantly associated with MAP use. In contrast, neither anxiety disorder nor depressive disorder was associated with MAP use. The association between the number of psychiatric comorbidities and MAP use was also tested, with the results showing that the greater the variety of lifetime psychiatric comorbidities, the higher the proportion of MAP users.
Attitude and knowledge The association between attitude and knowledge with respect to MAP use is shown in Table 2. The results reveal that subjects in the index group were more inclined towards MAP use and had less knowledge of its consequences than controls.
Family characteristics The association between each family characteristic dimension and MAP use is presented in Table 2. With respect to the family background, more MAP users had had disrupted parenting and/or family members with illicit drug use than their non-using counterparts. In addition, MAP use was associated with lower caregiver educational level and more siblings. Of the family interaction factors, the MAP-use subjects assessed their level of family conflict as lower compared to controls. No difference was demonstrated for family monitoring or family support comparing the two groups, however.
Peer factors The association between peer factors and MAP use is presented in Table 2, with more MAP users having
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Table 1. Psychiatric morbidity prevalence: lifetime prevalence Index (n = 200) n (%)
Control (n = 400) n (%)
χ2
OR
95% CI
Conduct disorder Attention-deficit/hyperactivity disorder Oppositional defiant disorder Depressive disorder Major depressive disorder Dysthymic disorder Adjustment disorder Anxiety disorder Specific phobia Social phobia Generalized anxiety disorder MAP-induced anxiety disorder School refusal Other MAP-induced psychotic disorder
90 (45) 50 (25) 1 (0.5) 18 (9) 9 (4.5) 9 (4.5) 24 (12) 61 (30.5) 30 (15) 30 (15) 6 (3) 6 (3) 3 (1.5) 3 (1.5) 15 (7.5)
10 (2.5) 42 (10.5) 6 (1.5) 22 (5.5) 7 (1.8) 15 (3.8) 18 (4.5) 102 (25.5) 51 (12.8) 47 (11.8) 16 (4) 0 12 (3) 9 (2.3) 0
173.4*** 21.6*** –† 2.6 3.9 0.2 11.5** 1.7 0.6 1.3 0.4 – 1.2 –† –
31.9 2.8 0.3 1.7 2.6 1.2 2.9 1.3 1.2 1.3 0.7 – 0.5 0.7 –
16.1–63.4 1.8–4.5 0.04–2.8 0.9–3.2 0.9–7.2 0.5–2.8 1.5–5.5 0.9–1.9 0.7–2.0 0.8–2.2 0.3–1.9 – 0.1–1.8 0.1–3.3 –
No. psychiatric morbidities None One Two or more
66 (33) 62 (31) 72 (36)
249 (62.3) 114 (28.5) 37 (9.3)
11.9** 75.0***
2.1 7.3
1.4–3.1 4.5–11.9
Any psychiatric morbidity
134 (67)
151 (37.8)
45.7***
3.3
2.3–4.8
CI, confidence interval; MAP, methamphetamine; OR, odds ratio; other: including panic disorder, agoraphobia, obsessivecompulsive disorder and post-traumatic stress disorder. † Two-tailed P from Fisher’s exact test >0.05. **P < 0.01; ***P < 0.001.
friends who were also users or providers of the drug to others in comparison to non-using controls. In addition, MAP users reported more active interaction with peers and greater numbers of friends with delinquent behaviors than controls. Of the peer interaction factors, users of MAP tended to be more frequently involved in social activities that increased the risk of contact with MAP than non-users. However, there were no between-group differences in ranking within and subjective perception with respect to the peer group, or ability to resist peer pressure.
Conditional logistic regression analysis Significant variables from univariate analyses were further analyzed using conditional logistic regression models. As shown in Table 3, the diagnosis of lifetime conduct disorder, and an attitude favoring MAP use and poor knowledge of its consequences were significantly associated with MAP use. Further, disrupted parenting, friends using or providing MAP, and more active peer interaction were significantly associated
with MAP use. By contrast, higher caregiver education level decreased the risk of MAP use.
DISCUSSION Methodological considerations Case definition is one of the most important considerations in any study of substance use. Underreporting is not uncommon in self-reporting questionnaire survey; it is therefore difficult to assess the characteristic physical and psychological symptoms, clinical signs and behavior attributed to substance use.32 In the present study, MAP use was proved for all subjects in the index group by urine test. A standardized clinical interview was also conducted by a psychiatrist who was experienced in the assessment of clinical syndromes that may, or may not, be caused by MAP use. The use of the culturally relevant Chinese version of the K-SADS-E has further ensured the study’s cross-cultural validity. Further, case–control design ensured accurate assessment of the association between MAP use and various indi-
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Table 2. Family characteristics, peer influence, attitude and knowledge of MAP use Index (n = 200)
Control (n = 400)
P
OR
95% CI
Family characteristics, n (%) Having disrupted parenting Illicit drug use in family members
109 (54.5) 30 (15)
53 (13.3) 8 (2)
115.1***† 38.5***†
7.8 8.8
5.3–11.7 3.9–19.5
Peer factors, n (%) Friends using or providing MAP
148 (74)
26 (6.5)
295.0***†
40.9
24.6–68.0
6.9 ± 2.9
2.9 ± 1.8
−17.4***‡
2.7 ± 1.0 1.9 ± 1.2 3.0 ± 0.5 3.0 ± 0.8 3.0 ± 0.6
3.5 ± 0.9 1.6 ± 0.9 2.9 ± 0.5 3.1 ± 0.6 3.1 ± 0.6
9.6***‡ −2.9**‡ −2.2*‡ 1.4 1.9
3.0 ± 0.5 2.8 ± 0.5 3.0 ± 0.5 4.1 ± 0.6 2.6 ± 0.5
2.9 ± 0.5 2.1 ± 0.5 2.9 ± 0.5 4.5 ± 0.5 2.9 ± 0.5
−1.8 −14.7***‡ −1.9 6.9***‡ 7.4***‡
Attitude and knowledge of MAP use (mean ± SD) Family characteristics Caregiver education No. siblings Family conflict Family monitoring Family support Peer factors (mean ± SD) Rank and feeling in peer group Active interaction with peers Self-efficacy to resist peer pressure Delinquent peer behavior Involved in social activities increasing the risk of abuse
CI, confidence interval; MAP, methamphetamine; OR, odds ratio. † 2 χ test; ‡t-test. *P < 0.05; **P
