Systematic review and meta-analysis of executive function following remission from major depression.

Background: Executive function is significantly impaired during an acute episode of major depressive disorder (MDD). Following remission, executive deficits recede but whether they fully dissipate is unclear. Evidence is also mixed on the extent to which persisting deficits reflect decreased processing speed or a distinct executive dysfunction.

Methods: We aimed to systematically evaluate how executive function following MDD remission compares to normal function, specify the pattern and severity of persistent deficits, examine prespecified moderators' effects, and determine if processing speed explains observed executive dysfunctions. Electronic databases and relevant reviews were systematically searched for studies published from January 1^st, 1972, to April 23, 2024. Main outcome was the difference in test performance between MDD remitters and healthy controls. Effect sizes were calculated with random-effects models. Significant moderators of between-study variability were combined to identify the best goodness-of-fit model using multiple method of moments meta-regressions.

Results: Sixty-one variables from 244 studies (12814 MDD remitters; 10578 healthy controls) were meta-analysed. Significant deficits relative to controls were found in all but one speed-constrained executive tests, with effect sizes ranging from small (g=0.24) to large (g=0.86). Between-group differences became non-significant after controlling for processing speed. MDD remitters and controls had comparable performance on unconstrained by speed tests of executive function, except for auditory and spatial working memory where negligible (g=0.19) to small (g=0.31) deficits were observed.

Conclusions: The executive dysfunction observed in auditory working memory, set-shifting, inhibition, planning, fluency and intellectual functioning following depression remission is largely explained by persistent impairment in processing speed.