Impairments in Cognitive and Psychomotor Performance Related to Antidepressant Drugs.

Major depressive disorder and the use of antidepressant drugs have both been associated with impairments in cognitive and psychomotor performance. Many factors affect prescribing decisions, for example efficacy, tolerability, the presence of co-morbid conditions and cost. The present review suggests that the potential of each antidepressant to further disrupt cognitive and psychomotor function in depressed patients should also be considered. An extensive review of the literature identified 64 studies of antidepressants in which cognitive and psychomotor function were assessed with objective psychometric tests in healthy volunteers. A database was compiled and results from double-blind, placebo-controlled, crossover studies were combined and analysed to determine the frequency and extent of impairments produced by as many antidepressants as possible on a battery of psychometric tests. Where statistically significant evidence of impairment was observed, this was recorded and used to calculate an impairment ratio for each antidepressant, which was subsequently compared with the impairment ratio obtained for all other antidepressants included in the review. Cohen’s d effect size estimates were also calculated in order to give an indication of the magnitude of impairments. The heterogeneity of the drugs and methods of measurement involved in this review have highlighted the limitations of the meta-analytic method used, and contrary to expectation has not allowed firm conclusions to be drawn