LAUSR

OBJECTIVE S100B is a glial cell protein with bimodal function. In low concentrations, it exerts neurotrophic effects, but higher levels reflect neuronal distress. Recent research suggests that this molecule may be a biomarker of response to electroconvulsive therapy (ECT). We examined the effect of ECT on serum S100B and its utility as 1) a biomarker of a depressive state and 2) a predictor of ECT response. We also wanted to ensure that ECT does not cause a marked serum S100B-elevation, indicating neural distress. METHODS We measured serum S100B in 22 in-patients treated with ECT due to depression. Depression severity was assessed using 17-item Hamilton Rating Scale for Depression (HAMD-17). The data were collected before an ECT series, within one week after the series (post-ECT), and at a six-month follow-up. Changes in serum S100B and clinical outcomes were tested using a linear mixed model. A relationship between serum S100B and the clinical outcomes was examined using Spearman and partial correlation. RESULTS Serum S100B did not change significantly immediately after an ECT series or six months later. The post-ECT serum S100B-change was not associated with the clinical effect (rho=.14, n=22, p=.54). The baseline serum S100B did not predict the clinical effect when controlling for age (r =.02, n=22, df=19, p=.92). CONCLUSION The study neither supports serum S100B as a state marker of depression nor a predictor of ECT response. No evidence for ECT-related neural distress was found.