Neural dynamics of resting-state EEG microstates in youth major depressive disorder with suicidal ideation

Youth major depressive disorder (MDD) is a debilitating condition associated with high rates of suicidal behavior. Although abnormal neuroimaging alterations have been reported in MDD patients with suicidal ideation (SI), little is known about the mechanisms of brain dynamics at high temporal resolution. This cross-sectional study included 177 participants aged 15–30 years: 95 with drug-naïve MDD (53 with SI, 42 without SI) and 82 healthy controls. All participants underwent a standardized 5-minute resting-state electroencephalography (EEG) acquisition. Comprehensive clinical assessments were administered, including the collection of psychosocial data and evaluation of suicide risk using the Beck Scale for Suicide Ideation (BSI-C). Group differences in microstate parameters were analyzed, and correlations between these parameters and clinical variables were examined. Resting-state EEG microstate analysis indicated that the SI group, relative to the NSI group, exhibited higher occurrence, coverage, and duration of microstate A, along with decreased indices for microstate B and reduced occurrence (but not coverage or duration) of microstate D. Alterations in transition probabilities were most prominent in microstates A and B, highlighting specific network-level differences associated with SI. In the SI group, BSI-C scores were positively correlated with the transition probability from C to B. Our findings suggest that young individuals with MDD and SI show specific changes in microstates, especially A and B. These findings reveal altered EEG microstate dynamics associated with SI in young MDD patients and may inform future research on neurophysiological correlates of suicidal ideation.