Thioridazine Effects on the Cognitive Performance of Children with Attention-Deficit Hyperactivity Disorder

Abstract

The use of neuroleptics in children with attention-deficit hyperactivity disorder (ADHD) is controversial for various reasons, including the concern that these medications may have deleterious effects on cognitive performance. This study compares the short-term (4 week) effects of thioridazine with a placebo in hyperactive children with ADHD. Thirty-seven children received thioridazine, and 40 received a placebo for 4 weeks in a double-blind study. Treatment was then maintained for a total of 12 weeks, with the last 8 weeks of treatment conducted in non-blind fashion. Mean daily dose of thioridazine was 193 mg at 4 weeks and 160 mg at 12 weeks. At 4 weeks, a variety of psychometric tests revealed no significant decrements in cognitive performance on thioridazine, except for the WISC Coding subtest. At 12 weeks, only the qualitative score on the Porteus Maze test was significantly worse on thioridazine. This study employed higher neuroleptic doses, longer treatment periods, and more neuropsychological measures than prior studies on the cognitive effects of neuroleptic agents in children with ADHD. The results are not consistent with expectations of significant decrements in cognitive test performance in ADHD children receiving thioridazine at these doses. Nonetheless, sedative effects of neuroleptics might interfere with school performance even in the absence of test deficits.