The course of insulin-like growth factor levels during electroconvulsive therapy

Electroconvulsive therapy (ECT) is highly effective for treating severe psychiatric disorders. The molecular mechanisms underlying these disorders, and ECT's effects remain incompletely understood. ECT may modulate growth factors and cytokines. Insulin-like growth factors (IGF)s link to neurogenesis and are altered in psychiatric disease. Data on longitudinal effects of ECT on the IGF-system across different psychiatric diagnoses, including IGF-1, IGF-binding protein 3 (IGFBP-3), IGF-2 and IGF-1/IGFBP-3 as proxy for free, active IGF-1 and its link to treatment response, is lacking. Patients undergoing ECT (n = 32) with mood disorders (n = 25) and psychotic disorders (n = 7) were investigated for IGF-1 and IGFBP-3, IGF-1/IGFBP-3 (quantified by CLIA) and IGF-2 (ELISA). Serum baseline IGF-levels were compared to levels after the sixth and last ECT and related to therapy response (global clinical improvement (CGI-I) ≤ 2 after last ECT). Associations of IGF-levels with CGI-I score were analyzed. IGF-1, IGF-1/IGFBP-3 but not IGF-2 were higher after the sixth ECT than baseline (p = 0.009; p = 0.031), adjusted for age, sex, BMI, main diagnosis and therapy response. IGF-levels did not differ between responders and non-responders. Lower global clinical improvement was linked with higher IGF-1 levels (p = 0.021), but not IGF-1/IGFBP-3 (p = 0.070), after adjusting for confounders. To our knowledge, this is the first study to longitudinally investigate the IGF-system across psychiatric diagnoses during ECT. IGF-1 and IGF-1/IGFBP-3 were elevated after the sixth ECT, independent of response. Higher symptom burden linked to higher IGF-1 and IGF-1/IGFBP-3. The observed changes may reflect neuroplastic processes, warranting mechanistic studies, but given the limited sample size, require confirmation in larger longitudinal studies.