Objective: Adults with attention-deficit/hyperactivity disorder (ADHD) have higher rates of alcohol and drug use disorders than adults without ADHD. The study aim was to determine if atomoxetine was superior to placebo in improving ADHD and alcohol use in recently abstinent adults with ADHD and comorbid alcohol use disorder.
Methods: Adults with DSM-IV diagnoses of ADHD and alcohol abuse and/or dependence were abstinent from alcohol at least 4 days (maximum 30 days) before study randomization. Participants received atomoxetine (25-100mg daily) or placebo for 12 weeks. ADHD symptoms were assessed using ADHD Investigator Symptom Rating Scale (AISRS) total score. Time-to-relapse to heavy alcohol use was analyzed using a 2-sided log-rank test based on Kaplan-Meier estimates and cumulative heavy drinking events over time were evaluated post hoc with recurrent-event analysis.
Results: Subjects received atomoxetine (n=72) or placebo (n=75) and 80 subjects completed the 12-week double-blind period (n=32 and 48, respectively). ADHD symptoms were significantly improved in the atomoxetine cohort compared to placebo (AISRS total score mean [S.D.], atomoxetine: -13.63 [11.35], P<.001; placebo: -8.31 [11.44], P<.001, difference: P=.007; effect size=0.48). No significant differences between treatment groups occurred in time-to-relapse of heavy drinking (P=.93). However, cumulative heavy drinking days were reduced 26% in atomoxetine-treated subjects versus placebo (event ratio=0.74, P=.023). There were no serious adverse events or specific drug-drug reactions related to current alcohol use.
Conclusions: This 3-month, double-blind, placebo-controlled study of atomoxetine in adults with ADHD and comorbid alcohol use disorder demonstrates clinically significant ADHD improvement, and inconsistent effects on drinking behavior.