Effects of antidepressants, anesthetics and sedatives/hypnotics on sleep-associated memory consolidation – A systematic review

Considering the wide and increasing utilization of drugs which act upon the central nervous system, a pressing, infrequently investigated question is their potential impact on sleep-associated memory consolidation. Here the influence of approved pharmaceuticals on memory consolidation during sleep in healthy humans, rats, and mice was investigated. A systematic review of the literature was conducted according to PRISMA guidelines. Criteria to be met included healthy subjects, drug application after learning and a comparable placebo condition. Exclusion criteria included but were not limited to repetitive dosing and additional non-pharmacological interventions. A total of 65 studies were included, whereby a limited number of studies lent themselves to a meta-analysis. The risk-of-bias assessment showed a lack of reporting predominantly in animal studies. Meta-analysis was conducted for the influence of zolpidem on consolidation of the word-pair association task in human adults, which showed an improvement in memory consolidation (0.57 (95% confidence interval 0.04–1.10)). Most importantly, for memory consolidation, results point toward a favorable position of second-generation antidepressants compared to their first-generation counterparts. Knowledge of such cognitive effects in healthy subjects should encourage consideration in designing studies with patients and/or in patient care.