Electroconvulsive Therapy and Ketamine Infusion in Patients with Bipolar I or II Depression: A Case Series

To compare the efficacy and safety of electroconvulsive therapy (ECT) and ketamine infusion (KET-IFU) in routine care for patients with bipolar I or II depression (BPD).

Electronic medical records of patients who received ECT and/or KET-IFU were used to identify patients with BPD who received both ECT and KET-IFU treatments. The change in the 16-item Quick Inventory of Depressive Symptomatology Self-Report (QIDS-16-SR) total score was used as an efficacy outcome. Self-reported side effects and Montreal Cognitive Assessment (MoCA) were used as safety measures.

Six patients with BPD received both ECT and KET-IFU treatments. All patients received ECT first. Five patients received KET-IFU due to subjective memory concerns from ECT although their MoCA scores were within normal range. One patient with multiple previous ECT series received two KET-IFU series followed by an ECT series. Four patients responded to acute ECT treatments well with ⩾ 50% improvement in QIDS-16-SR total scores. Two of them also responded to KET-IFU well with ⩾ 50% improvement but the onset of antidepressant effect differed. One patient did not respond to ECT or KET-IFU. The patient who had two series of KET-IFU responded well during the first KET-IFU series but had limited benefit from the second KET-IFU series. No patient discontinued KET-IFU due to an adverse event.

Most patients responded to ECT well and half of them had similar benefit from KET-IFU as from ECT. Randomized, head-to-head comparison studies of ECT versus KET-IFU in BPD are warranted to confirm or refute these findings.