Uncovering oscillatory dysregulation associated with suicide risk in major depressive disorder: a narrative review.

Neural oscillations have emerged as critical markers of cognitive and emotional states, offering valuable insights into psychiatric disorders. Given the potential suicide risk in patients with major depressive disorders (MDD), its underlying neurophysiological associations need to be further elucidated. This review aimed to comprehensively examine the complex relationships between neural oscillations and suicide risk in MDD. We performed a detailed analysis of electrophysiological phenomena reported in studies investigating suicide risk within depressive populations, consisting of event-related potentials (ERPs) and neuronal oscillations across theta, delta, alpha, beta, and gamma frequency bands. Notably, reduced P300 amplitude, associated with cognitive dysfunction, was observed with elevated theta and delta activity in brain regions implicated in emotional processing, correlating with heightened susceptibility to suicidal behavior. Altered alpha and beta oscillations were associated with emotional dysregulation and cognitive deficits. Importantly, gamma oscillations exhibited increased activity in individuals with suicidal tendencies, reflecting disruptions in the balance between excitatory and inhibitory neuronal circuits. Despite these findings, current research was limited by heterogeneity among study populations, small sample sizes, challenges in establishing causality, and an incomplete understanding of the biological associations underpinning these oscillations. Future research should focus on integrating multi-dimensional oscillatory features to improve individual risk prediction, employing longitudinal designs to track dynamic changes over time, and developing targeted interventions. Addressing these challenges will be critical for advancing reliable biomarkers and innovative strategies for suicide prevention in depression.