The novel seizure quality index for the antidepressant outcome prediction in electroconvulsive therapy: association with biomarkers in the cerebrospinal fluid.

For patients with depression treated with electroconvulsive therapy (ECT), the novel seizure quality index (SQI) can predict the risk of non-response (and non-remission)-as early as after the second ECT session-based the extent of several ictal parameters of the seizure. We aim to test several CSF markers on their ability to predict the degree of seizure quality, measured by the SQI to identify possible factors, that could explain some variability of the seizure quality. Baseline CSF levels of metabolites from the kynurenine pathway, markers of neurodegeneration (tau proteins, β-amyloids and neurogranin), elements of the innate immune system, endocannabinoids, sphingolipids, neurotrophic factors (VEGF) and Klotho were measured before ECT in patients with depression (n = 12) to identify possible correlations with the SQI by Pearson's partial correlation. Negative, linear relationships with the SQI for response were observed for CSF levels of T-tau (rpartial = - 0.69, p = 0.019), phosphatidylcholines (rpartial = - 0.52, p = 0.038) and IL-8 (rpartial = - 0.67, p = 0.047). Regarding the SQI for remission, a negative, linear relationship was noted with CSF levels of the endocannabinoid AEA (rpartial = - 0.70, p = 0.024) and CD163 (rpartial = - 0.68, p = 0.029). In sum, CSF Markers for the innate immune system, for neurodegeneration and from lipids were found to be associated with the SQI for response and remission after adjusting for age. Consistently, higher CSF levels of the markers were always associated with lower seizure quality. Based on these results, further research regarding the mechanism of seizure quality in ECT is suggested.