Association between the novel seizure quality index for the outcome prediction in electroconvulsive therapy and brain-derived neurotrophic factor serum levels.

The novel Seizure Quality Index (SQI) could predict the risk of non-response and non-remission as early as after the second electroconvulsive therapy (ECT) session based the extent of several ictal parameters of the seizure in patients with depression. The association between those indices with the peripheral serum levels of brain-derived neurotrophic factor (BDNF) was evaluated in this study. It was proposed that seizure quality reflected by the SQI will be positively correlated with the levels of serum BDNF after ECT in patients with depression. We included 36 patients with a full data set, a completed course of ECT and BDNF levels before and after that ECT course. Baseline serum BDNF levels (2838.9 pg/ml ±1659.9) were lower compared to the mean BDNF levels after ECT (3206.3 pg/ml ±1532.3), but the statistical test did not reach significance (z = 1.96, p = 0.051, r = 0.23). In a sub-group analysis, the BDNF levels after ECT were positively correlated with the SQI sum score for response (rs = 0.62, p = 0.018) and for remission (rs = 0.57, p = 0.033) in patients younger than 65 years, the group, for whom the SQI has been built and validated. This suggests that one link between seizure quality and antidepressant response to ECT could be BDNF.