Is attention-deficit/hyperactivity disorder associated with illicit substance use disorders in male adolescents? A community-based case-control study.

AIMS

This study aims at evaluating the association between attention-deficit/hyperactivity disorder (ADHD) and illicit substance use disorders (SUD) (marijuana, cocaine and inhalants), controlling for the association with conduct disorder (CD), in a community-based sample of adolescents.

DESIGN

Case-control, community-based study.

SETTING

A delimited geographical area in the South of Brazil, served by four public health clinics.

PARTICIPANTS

A total of 968 male adolescents (15-20 years of age) were screened for SUD in their households. Of the subjects who were screened positive, we selected 61 cases with illicit SUD. For each case we selected, from the group which was screened negative, three controls without illicit or alcohol SUD, matched by age and proximity with the case's household.

MEASUREMENTS

The screening instrument was the Alcohol Smoking and Substance Screening Test (ASSIST). SUD diagnoses were assessed by the drug section of the Mini International Neuropsychiatry Interview (MINI). Other psychiatric diagnoses were based on semistructured (Schedule for Affective Disorders and Schizophrenia for School-Age Children-epidemiological version; MINI) and clinical interviews.

FINDINGS

Adolescents with ADHD presented a significantly higher odds ratio (OR) for illicit SUD than youths without ADHD, even after adjusting for potential confounders (CD, ethnicity, religion and estimated IQ) (OR = 9.12; 95% CI = 2.84-29.31, P < 0.01).

CONCLUSIONS

Our results suggest an association between ADHD and illicit SUD in Brazilian adolescents that is not mediated by CD. These findings are potentially important from a prevention perspective because treatments are available for ADHD.