Frontal Alpha Asymmetry Correlates with Suicidal Behavior in Major Depressive Disorder

OBJECTIVE: Based on the constant associations made between major depressive disorder (MDD) and alpha asymmetry, and MDD and suicide, this study aimed to examine the relationship between frontal alpha asymmetry and suicide in MDD patients. METHODS: Sixty-six MDD patients, of whom fifteen were male and fifty-one were female, were recruited. Independent groups were created based on the median score of frontal alpha asymmetry: the left dominant (LD) group and the right dominant (RD) group. The alpha band (8–12 Hz) and its sub-bands (i.e., low alpha band: 8–10 Hz; high alpha band: 10–12 Hz) were of interest. Source level alpha asymmetry was calculated as well. RESULTS: Suicidal behavior was positively correlated with the asymmetry indices of the low alpha band and the alpha band in the LD group and that of the high alpha band in the RD group. Source level analysis revealed positive correlations between suicidal behavior and the asymmetry index of the low alpha band in the LD group. CONCLUSION: Frontal alpha asymmetry, especially that of the low alpha band, might reflect the cognitive deficits associated with suicidal behaviors in MDD patients.