Effects of antidepressants on cognitive functions: a review

The widespread use of antidepressants since the late 1950s and especially the ambulatory treatment of the majority of depressive patients raises the issue of the state of knowledge of the effects of these drugs on cognitive function. This review aims at synthesizing information about differential effects of antidepressants on cognitive function to facilitate good prescription. The first part of this review tries to summarize the main tasks used to explore global reactivity, attention, memory and psychomotor performances. The second part of this work presents the differential cognitive effects of antidepressants with a discrimination between substances which have a sedative impact, antidepressants with no cognitive effect, and drugs which seem to have a positive cognitive action. The differenciation is established for single and repeated administration, for healthy volunteers and depressed subjects. For each substance, the dose, the tasks selected and cognitive effect are discussed and the question of the real benefit of this cognitive impact is raised. The specificity of cognitive effects of antidepressants related to age and to the combination with alcohol are also tackled. Then the discussion raises the difficulty and the biases encountered to perform neuropsychological studies and particularly evaluation of cognitive effects of antidepressants. Finally the conclusion of this review gives some advice to select and prescribe antidepressants according to their cognitive effects.