Cognitive Dysfunction and Learning Implications in Medical Students With Depressive Symptoms: Electrophysiological Evidence From P300 Event-Related Potentials

INTRODUCTION: Major depressive disorder is highly prevalent among medical students and strongly associated with cognitive dysfunctions. OBJECTIVE: To compare neuropsychological and electrophysiological profiles (P300 parameters) of medical students with and without depressive symptoms. METHODS: A cross-sectional and comparative study was conducted with 140 second-year medical students. Depressive symptoms were assessed with the Patient Health Questionnaire-9. Cognitive performance was evaluated with the Montreal Cognitive Assessment (MoCA) and CogniFit (CogniFit Inc., San Francisco, CA, USA) computerized tests. Event-related potentials were recorded through a standard auditory oddball paradigm, analyzing N100, N200, and P300 latency and amplitude. Statistical analyses included independent sample t-tests and analysis of variance, with significance set at p < 0.05. Effect sizes (Cohen's d) were reported for all group comparisons, and appropriate corrections for multiple comparisons were applied to control type I error. RESULTS: Students with depressive symptoms exhibited slower response time (p < 0.01), processing speed (p = 0.01), impaired contextual memory (p =.01), short-term memory (p = 0.01), working memory (p = 0.01), focused attention (p = 0.01) and perception domain( p = 0.03). On the MoCA, lower in abstraction (p = 0.03), delayed memory recall (p < 0.01), and total MoCA score (p = 0.008). Event-related potentials analysis revealed significantly prolonged latencies for N100, N200, and P300 (all, p < 0.01), and decreased amplitudes in N100, N200, and P300 (p < 0.05). Prolonged event-related potentials latencies (particularly P300) correlated negatively with performance on processing speed (r = -0.39, p < 0.001), focused attention (r = -0.32, p < 0.001), and delayed recall (r = -0.31, p < 0.001). CONCLUSIONS: Medical students with depressive symptoms demonstrate specific cognitive impairments and altered event-related potential markers, reflecting reduced attentional efficiency and information processing. Combining computerized neuropsychological testing with electrophysiological measures may provide a feasible screening pathway for cognitive vulnerability among medical trainees and guide the development of preventive and educational interventions within medical curricula.