Short-term lithium treatment modulates excitation/inhibition balance in resting-state electroencephalography (EEG) among survivors of medically severe suicide attempts.

Short-term lithium treatment may reduce impulsivity and suicide risk by stabilizing cortical signaling in high-risk individuals. The present double-blind, placebo-controlled, crossover study enrolled survivors of medically severe suicide attempts and recorded 2-min eyes-open resting-state electroencephalography at baseline (drug-naïve), after 4 weeks of lithium carbonate, and after 4 weeks of placebo (n = 10 completers). Analysis focused on spectral power across traditional frequency bands (delta through gamma) and the aperiodic slope of the power spectrum, a marker of excitation/inhibition balance in cortical networks. Treatment with lithium significantly increased gamma-band power relative to both baseline and placebo and flattened the aperiodic slope compared to baseline (p < .001). Other frequency band changes (beta, alpha) showed drug effects in analysis of variance but lacked consistent post hoc support. The increase in gamma power and alteration in aperiodic slope suggest engagement of cortical network mechanisms consistent with restored excitation/inhibition balance and enhanced neural synchrony. These preliminary neurophysiological findings support the possibility that electroencephalography-based measures could serve as objective biomarkers for lithium's neural effects in individuals at high suicide risk and warrant further large-scale studies integrating behavior and neurochemistry. (PsycInfo Database Record (c) 2026 APA, all rights reserved).