Cognitive performance in depressed patients after chronic use of antidepressants

Abstract

Rationale: Depressive disorders are conditions that often require continuous treatment, and it is therefore important to evaluate the consequences of prolonged administration. There are few studies assessing cognitive functions of depressed patients after long-term use of antidepressants.

Objectives: This study evaluated the cognitive performance of depressed patients treated with antidepressants for at least 6 months.

Methods: Patients with major depression (DSM-IV) using imipramine for 2.4+/-0.6 years (mean+/-SE), clomipramine for 2.8+/-1.2 years, fluoxetine for 1.8+/-0.3 years and sertraline for 1.5+/-0.3 years were compared to matched controls (sex, age and educational level) without any psychiatric diagnosis. Memory evaluation consisted of episodic, implicit and working memory tests as well as metamemory assessment.

Results: (a) Psychomotor performance of patients taking imipramine was worse than that of controls in inserting pins and a visual reaction time task; on the performance of tapping the difference from controls varied according to dose/weight for patients taking clomipramine and fluoxetine. (b) For memory tests, differences between patients taking sertraline and controls were observed in the number of digits and words recalled; the difference between patients and controls varied according to dose/weight on the number of familiar words correctly completed for patients taking clomipramine and on digit span backward for those taking sertraline. (c) Metamemory was worse in all patient groups irrespective of patients' clinical state.

Conclusions: The impairment in psychomotor and memory performances associated with these antidepressants seems to be of low intensity and of questionable clinical relevance.