• adult attention deficit/hyperactivity disorder;
  • double-blind controlled trial;
  • venlafaxine


Attention deficit/hyperactivity disorder (ADHD) is one of the most common mental disorders beginning in childhood that may continue to adulthood. The purpose of this study was to evaluate the possible therapeutic effect of venlafaxine in adults with ADHD.


In a double-blind setting, drug-naïve adults with a diagnosis of ADHD based on DSM-IV-TR criteria were randomly selected to receive either venlafaxine (up to 225 mg/day) or a placebo for 6 weeks. The Conners Adult ADHD Rating Scale self-report screening version was administered before and during the treatment at 2-week intervals to measure the therapeutic effects.


The mean age (SD) of patients was 30.5 (8.1) years. Eleven out of 20 patients receiving venlafaxine and 13 out of 21 patients receiving the placebo were male. The two groups were not significantly different in terms of age, educational level, weight, or blood pressure.

Significant decrease was observed in both subscales (inattentive, hyperactive/impulsive), total ADHD symptoms score, and ADHD index in both the venlafaxine and the placebo groups. Seventy-five percent of treatment group versus 20% of placebo group met treatment response criteria when defined as a 25% drop in total ADHD score (p = 0.001).

No serious adverse effects were reported during the trial.


In this double-blind trial, the symptoms of adult ADHD decreased after a 6-week trial of either venlafaxine or a placebo with no significant difference. However, a significant treatment response defined as a 25% drop in ADHD index (measured by a self-report scale) was achieved by venlafaxine. The interpretation of these results is limited by the short duration of follow-up in this study. Copyright © 2012 John Wiley & Sons, Ltd.