A meta-analytic review of the relationship between explicit memory bias and depression: Depression features an explicit memory bias that persists beyond a depressive episode.

Emotional bias in explicit memory is theorized to play a prominent role in the etiology, maintenance, and recurrence of depression.Even though this cognitive bias is regarded as one of the most robust phenomena in depression, its magnitude and boundary conditions in depression are currently unknown.This review presents two three-level meta-analyses to estimate the overall effect size and identify moderators of explicit memory bias in depression.Meta-analysis I (153 studies, 686 contrasts) revealed a small overall effect size for naturalistic explicit memory bias in depression (g=0.241,95% CI [0.179, 0.304]).The magnitude of the overall effect was moderated by emotional valence of stimuli, operational definition of memory bias, depth of processing during encoding, explicit memory task, and the (non-)verbal nature of stimuli.Equivalent effect sizes were found for minors and adults as well as for clinical and subclinical depression.Remarkably, a non-significant effect size emerged for remitted depression.Following up on the latter finding, meta-analysis II (21 studies, 80 contrasts) examined explicit memory bias in remitted depression under naturalistic conditions and under mood/stress induction.Results yielded a nonsignificant overall effect size, g=0.131, 95% CI [-0.045, 0.307], but a significant effect size for study conditions with mood or stress induction, g=0.273, 95% CI [0.004, 0.542].Both meta-analyses indicated high levels of heterogeneity, even after accounting for variation explained by sample and study characteristics.The findings are consistent with the view that depression is characterized by an explicit memory bias that may persist beyond a depressive episode.These findings have implications for cognitive theories of vulnerability to depression as well as clinical interventions.