A Randomized Double-Blind Trial of Paroxetine and/or Dextroamphetamine and Problem-Focused Therapy for Attention-Deficit/Hyperactivity Disorder in Adults

Margaret Weiss, M.D., Ph.D.; Lily Hechtman, M.D.; and The Adult ADHD Research Group

Objective: To determine the effect of psychotherapy, dextroamphetamine, and/or paroxetine on attention-deficit/hyperactivity-disorder (ADHD) in adults.

Method: Ninety-eight adults with DSM-IV ADHD were randomly assigned to receive psychotherapy and dextroamphetamine, paroxetine, both, or placebo for 20 weeks. A 2x2 factorial design compared patients who received dextroamphetamine versus no dextroamphetamine with patients who received paroxetine versus no paroxetine. Data were collected from August 2000 until May 2002.

Results: One half of the 98 enrolled subjects were found to have at least 1 lifetime mood or anxiety disorder on the Structured Clinical Interview for DSM-IV. Sixty percent of patients who received medication and 80% of those who received placebo completed the 5-month trial. ADHD symptoms were significantly (p = .012) lower in patients in the completer group who received dextroamphetamine. Paroxetine had no effect on ADHD. Hamilton Rating Scales for Anxiety (HAM-A) and Depression (HAM-D) scores were low to start, and no treatment differences were evident at endpoint. Significantly (p < .001) more patients in the completer group were rated by clinicians as ADHD responders if they received dextroamphetamine (85.7%) or combined treatment (66.7%) versus paroxetine (20.0%) or placebo (21.1%). Significantly (p = .003) more patients in the completer group were rated by clinicians as mood/anxiety responders if they received paroxetine (100%) or combined treatment (73.3%)
versus those receiving dextroamphetamine (57.15%) or placebo (47.4%). Clinicians rated any patient who received medication and psychological therapy as significantly more improved overall than those who received placebo and psychological therapy (intent to treat: p = .033; completers: p = .001).

Conclusion: ADHD symptoms improved with dextroamphetamine. Mood and internalizing symptoms were seen as improved with paroxetine by clinicians, despite absence of response on the HAM-A and HAM-D. The presence of a lifetime internalizing disorder attenuated the response to dextroamphetamine. Patients who received both dextroamphetamine and paroxetine had more severe adverse events but did not show greater improvement overall than patients treated with 1 medication. Clinical Trials Registry #GSK707.

(J Clin Psychiatry 2006;67:611-619)

Received May 12, 2005; accepted Nov. 8, 2005. From the Department of Psychiatry, University of British Columbia, Vancouver, British Columbia (Dr. Weiss); and the Department of Psychiatry, McGill University, Montreal, Quebec (Dr. Hechtman), Canada.

This investigator-initiated trial was funded by GlaxoSmithKline, Research Triangle Park, N.C.

Individual financial disclosure appears at the end of this article.

Members of the Adult ADHD Research Group appear at the end of this article.

Corresponding author and reprints: Margaret Weiss, M.D., Ph.D., Division of Child Psychiatry, University of British Columbia, Children's and Women's Health Centre, Box #178, B430-4500 Oak St., Vancouver, British Columbia, Canada V6H 3N1 (e-mail: mweiss@cw.bc.ca).