When to switch from bilateral to unilateral electroconvulsive therapy: A simple way to elicit seizures in high seizure threshold cases

AIMS: Although electroconvulsive therapy (ECT) is effective for various psychiatric disorders, its therapeutic effect depends on the occurrence of adequate seizures. Thus, the management of inadequate seizures remains a clinical problem. Here, we aimed to develop a simple method to elicit adequate seizures in high seizure threshold patients during ECT sessions. METHODS: Right unilateral ECT was performed in 87 sessions (22 inpatients) in which 504 millicoulombs bilateral (bitemporal or bifrontal) electrical stimulation had failed to induce adequate seizures. A Thymatron(®) System IV (Somatics LLC, Lake Bluff, IL, USA) and the LOW 0.5 program were used in accordance with the manufacturer's instructions. The electrode placement was bitemporal, bifrontal, or right unilateral (d'Elia placement). The minimum duration for an adequate seizure was 15 seconds in the electroencephalogram record of the Thymatron(®) stimulator. The efficacy of treatment was estimated by the Global Assessment of Functioning at the time of admission and discharge. Cognitive assessment was not performed. RESULTS: By switching to right unilateral stimulation immediately after failure of bilateral stimulation, adequate seizures were achieved in 71 of 87 (81.6%) sessions. Improvement in the Global Assessment of Functioning was observed in 23 of 28 (82.1%) treatment courses. CONCLUSION: Switching from bilateral to unilateral electrode placement may be a simple clinical option for eliciting adequate seizures in high seizure threshold cases.