Prospective memory deficits in patients with depression: A meta-analysis

Background Prospective memory (PM) can be impaired in patients with psychiatric disorders including depression. This meta-analysis systematically examined PM in patients with depression. Methods The meta-analysis was conducted according to the guidelines from Strengthening the Reporting of Observational studies in Epidemiology (STROBE). Case-control studies on PM in patients with depression were included. Standardized mean differences (SMDs) and 95% confidence interval (CI) were calculated using random effect models. Results Ten case-control studies (n = 596) comparing patients with depression (n = 299) with healthy controls (n = 297) were included in the analyses. Compared with healthy controls, patients with depression had significant impairment in event-based PM (EBPM) [8 trials, n = 436; SMD: −0.87 (95%CI: −1.43, −0.31), P = 0.002; I² = 87%]. Significance was observed after removing two outlier trials [SMD: −0.44 (95%CI: −0.69, −0.20), P = 0.0004; I² = 23%] and also in 8 out of the 13 subgroup analyses. Similarly, time-based PM (TBPM) was significantly impaired in patients with depression [4 trials, n = 239; SMD: −0.89 (95%CI: −1.46, −0.31), P = 0.003; I² = 78%] when compared with healthy controls. Conclusions This meta-analysis showed that both TBPM and EBPM appeared to be impaired in patients with depression.