EEG Power Spectral Signatures of Looming Vulnerability Style in Individuals with a Recent Suicide Attempt

The Looming Vulnerability Model suggests that rapidly approaching or increasing threats, like visual looming stimuli, can potentially contribute suicidal thoughts and behaviors. This study investigates the neurobiological basis of this theory in suicide attempters, focusing on the EEG power spectrum.

In a case-control design, participants completed a visual Looming task involving threatening and neutral stimuli during EEG neuroimaging. The final sample included 15 participants with recent suicide attempts and major depressive disorder (SA+MDD), 19 participants with major depressive disorder (MDD), and 18 Healthy Controls (HC). EEG absolute power was calculated and group differences were analyzed using ANOVA with post-hoc tests.

Participants in the SA+MDD group showed significantly greater delta band power in frontopolar regions (AF3, Fp2, Fpz) compared to HC under both task conditions. Theta band power over the right frontal cortex during both conditions differentiated SA+MDD from MDD participants, while increased beta synchronization in the right premotor area distinguished SA+MDD from both MDD and HC, particularly during trials with neutral stimuli. Additionally, gamma band desynchronization to threatening stimuli was observed in SA+MDD compared to MDD.

The findings support a link between electrophysiological responses to looming stimuli and recent suicide attempts. Increased delta and theta power may reflect heightened emotional processing and sensitivity to threat or pain, while elevated beta activity may indicate increased demands on motor inhibition. Gamma desynchronization may reflect a residual vulnerability to suicidal behavior in the aftermath of a recent attempt.