Systematic review and meta-analysis: Impact of unipolar depression on P300 amplitude and latency

Depression is characterized by impairments of cognitive systems such as significant deficits in attention, memory, and cognitive control. The P300 (or P3) event-related potential (ERP) component has been extensively investigated over the past four decades to elucidate the underpinnings of these cognitive dysfunctions. Many studies have observed reduced P300 amplitude and prolonged P300 latency in individuals experiencing depression. The current study provides a comprehensive systematic quantitative review (i.e., meta-analysis) of the depression and P300 literature from 1981 to 2023 employing PubMed and ProQuest databases. Included articles quantitatively measured depression and P300 amplitude or latency. In total, 127 studies (total N = 12,722) comprised the current analyses (i.e., 116 examining P300 amplitude and 51 examining P300 latency), resulting in 601 effect sizes (i.e., 464 depression and P300 amplitude; 137 depression and P300 latency). Robust variance meta-regression results revealed a small significant negative effect size (r = -.15) between P300 amplitude and depression even after correcting for publication bias. There was a similar small significant positive effect size (r = .15) between P300 latency and depression. Findings from moderator analyses indicated that stimulus modality, medication use, and age impacted the P300 amplitude and depression effect size; no moderators of the P300 latency and depression relationship were observed. Regarding limitations, we did not exhaustively test all possible factors that may impact P300 and depression association. The current quantitative review confirms significant differences in P300 (both amplitude and latency) attributed to cognitive dysfunctions common in depression as well as guides future study designs and methodological approaches.