Abstract
Attention deficit hyperactivity disorder (ADHD) is one of the most commonly diagnosed disorders of childhood and is frequently observed in adults who are at increased risk for a number of comorbid conditions, including substance use problems. Although ADHD in adults is recognised, research on the topic is limited with even less research information available on Australian adults with ADHD. The present study examined prevalence of ADHD and conduct disorder (CD) and the association between ADHD and severity of drug use among 95 adult male drug users. Forty-six percent of participants met criteria for ADHD in adulthood, 36% had childhood ADHD, and 68% had CD. Adults with ADHD had higher childhood inattentive, childhood hyperactive-impulsive, CD, and antisocial behaviour scores compared to non-ADHD drug users, and in terms of drug use had more severe psychological dependence, more severe substance use (excluding alcohol), and higher quantity and frequency of use. The findings of the study indicate that ADHD is highly prevalent among male drug users and that ADHD in adulthood is associated with more severe drug use behaviours.