Error processing in major depressive disorder

Objective: Alterations in error-related negativity (ERN) and error positivity (Pe)—electrophysiological markers of error processing—have been frequently reported in major depressive disorder (MDD); findings, however, remain inconsistent. Methods: Literature search was performed using Web of Science, MEDLINE/PubMed, and Scopus electronic databases. The effect sizes (Hedges’ g) in the comparisons of ERN (22 studies) and Pe (10 studies) amplitudes between MDD and healthy controls (HC) were employed by a random-effect, inverse-variance weighted model. Results: ERN and Pe amplitudes in MDD patients were generally comparable to those of HC. Nevertheless, moderator analyses revealed specific conditions under which Pe amplitudes were reduced in MDD. Specifically, MDD patients with comorbid conditions showed diminished Pe amplitudes relative to HC (p = 0.001). Moreover, task type moderated Pe responses: studies using the Flanker task reported significantly reduced Pe amplitudes in MDD patients (p = 0.012), a pattern not observed with other paradigms. No significant moderators were identified for ERN amplitudes. Conclusions: Comorbidity and task design, particularly the use of the Flanker task, appear to influence Pe amplitudes in patients with MDD and should be carefully considered in future research. Significance: Our data highlight the importance of methodological factors in interpreting error processing deficits in MDD.