Atomoxetine and stroop task performance in adult attention-deficit/hyperactivity disorder.

The aim of this study was to assess the efficacy of atomoxetine, a new and highly selective inhibitor of the norepinephrine transporter, for executive functioning in adults with attention-deficit/hyperactivity disorder (ADHD). Two identical studies using a double-blind, placebo-controlled, parallel design were conducted. Patients were adults (Study 1, n = 280; Study 2, n = 256) with Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV)-defined ADHD recruited by referral and advertising. They were randomized to 10 weeks of treatment with atomoxetine or placebo. Executive functions were measured by the Stroop task. There was no evidence of cognitive deterioration associated with atomoxetine treatment. Atomoxetine treatment was associated with an improvement of the Stroop colorword score. Our results provide further support for Spencer et al.'s (1998) report that atomoxetine improves inhibitory capacity, as measured by the Stroop task. The absence of cognitive deterioration from atomoxetine, along with improved performance in a subgroup of patients in this large study, supports the safety of atomoxetine in this regard and its potential for improving a significant source of impairment for adults with ADHD.