Prospective effects of attention-deficit/hyperactivity disorder, conduct disorder, and sex on adolescent substance use and abuse.
BACKGROUND
Attention-deficit/hyperactivity disorder (ADHD), an early manifestation of externalizing behavior, may identify children at high risk for later substance abuse. However, the ADHD-substance abuse relationship often disappears when co-occurring conduct disorder (CD) is considered.


OBJECTIVE
To determine whether there is a prospective relationship between ADHD and the initiation of substance use and disorders, and whether this relationship depends on the ADHD subtype (hyperactive/impulsive or inattentive), CD, or sex.


METHODS
Dimensional and categorical measures of ADHD and CD were examined via logistic regression analyses in relation to subsequent initiation of tobacco, alcohol, and illicit drug use by 14 years of age and onset of substance use disorders by 18 years of age in a population-based sample of 11-year-old twins (760 female and 752 male twins) from the Minnesota Twin Family Study.


METHODS
Structured interviews were administered to adolescents and their mothers regarding substance use and to generate diagnoses.


RESULTS
For boys and girls, hyperactivity/impulsivity predicted initiation of all types of substance use, nicotine dependence, and cannabis abuse/dependence (for all, P < .05), even when controlling for CD at 2 time points. By contrast, relationships between inattention and substance outcomes disappeared when hyperactivity/impulsivity and CD were controlled for, with the possible exception of nicotine dependence. A categorical diagnosis of ADHD significantly predicted tobacco and illicit drug use only (adjusted odds ratios, 2.01 and 2.82, respectively). A diagnosis of CD between 11 and 14 years of age was a powerful predictor of substance disorders by 18 years of age (all odds ratios, > 4.27).


CONCLUSIONS
Hyperactivity/impulsivity predicts later substance problems, even after growth in later-emerging CD is considered, whereas inattention alone poses less risk. Even a single symptom of ADHD or CD is associated with increased risk. Failure in previous research to consistently observe relationships between ADHD and substance use and abuse outcomes could be due to reliance on less-sensitive categorical diagnoses.
Elkins
Irene J
IJ
Department of Psychology, University of Minnesota, 75 E River Road, Minneapolis, MN 55455, USA. ielkins@tfs.psych.umn.edu
McGue
Matt
M
Iacono
William G
WG
D000293:Adolescent; D000294:Adolescent Behavior / Q000523:psychology; D000367:Age Factors; D001289:Attention Deficit Disorder with Hyperactivity / Q000145:classification / Q000175:diagnosis* / Q000453:epidemiology*; D002648:Child; D015897:Comorbidity; D019955:Conduct Disorder / Q000175:diagnosis* / Q000453:epidemiology*; D004200:Diseases in Twins / Q000175:diagnosis* / Q000453:epidemiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D002189:Marijuana Abuse / Q000175:diagnosis / Q000453:epidemiology; D009035:Mothers / Q000523:psychology; D015995:Prevalence; D011336:Probability; D011379:Prognosis; D011446:Prospective Studies; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D012307:Risk Factors; D012737:Sex Factors; D019966:Substance-Related Disorders / Q000175:diagnosis* / Q000453:epidemiology*; D014029:Tobacco Use Disorder / Q000175:diagnosis / Q000453:epidemiology