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This page is an AI-assisted Turkish summary of the study presented at the 26th World Congress of Psychiatry. The study belongs to the presenting authors; please refer to the original source when citing it.

SO048

Neural correlates of ketamine’s antisuicidal response in treatment-resistant bipolar depression

NEURAL CORRELATES OF ANTI-SUICIDAL RESPONSE TO KETAMINE IN TREATMENT RESISTANT BIPOLAR DEPRESSION

Repeated intravenous ketamine infusions were safe and tolerable in bipolar depression and produced rapid improvements in depression severity and suicidality that lasted one month, but did not lead to significant changes in cortical excitation or inhibition.

The study aimed to evaluate the safety and tolerability of repeated ketamine infusions in bipolar depression (BD), examine changes in neurophysiological markers of cortical excitation and inhibition, and measure changes in depressive symptoms and suicidal ideation during treatment. This was a single-arm, open-label pilot study; 16 individuals were assessed for eligibility, and 11 were enrolled (the poster reported N = 16 assessed and N = 11 enrolled; the conference abstract reported 16 participants and n = 14 for neurophysiological measurements). Inclusion criteria were adult outpatients aged 24–65 years, a MINI-confirmed diagnosis of BD, and a major depressive episode with a Beck Scale for Suicidal Ideation (SSI) score of 9 or higher; exclusion criteria were a current manic episode, a substance use disorder, a primary psychotic disorder, an unstable medical condition, and a contraindication to transcranial magnetic stimulation (TMS). Ketamine infusions (0.5–0.8 mg/kg) were administered twice weekly for four weeks, and NMDA- and GABA-mediated neurotransmission was examined using TMS combined with electromyography (EMG), through measures of short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF). Regarding tolerability, a 100% retention rate throughout treatment and no serious adverse events were reported; transient increases in systolic and diastolic blood pressure (p < 0.001) were confined to the infusion period. Depression assessments using the Hamilton Rating Scale for Depression (HRSD) indicated a response rate of 27% and remission rates ranging from 9% to 18%, while SSI remission rates ranged from 36% to 45%. Ketamine-related improvement in depression was associated with baseline corticospinal excitability (p = 0.02; R = 0.70) and baseline cortical inhibition (p = 0.03; R = -0.64), but no significant changes in cortical excitation or inhibition were detected during treatment. In conclusion, repeated ketamine infusions were safe and tolerable in BD and produced rapid improvements in depression severity and suicidality that persisted at one month, while baseline cortical excitability and inhibition may predict the antidepressant effect.

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