# Variables associated with clinical outcomes and switching from unilateral to bitemporal electroconvulsive therapy: a retrospective study

## TL;DR

This study examines factors influencing outcomes in electroconvulsive therapy, focusing on when and why patients switch from unilateral to bitemporal ECT.

## Contribution

The study identifies clinical variables associated with the need to switch from unilateral to bitemporal ECT and their impact on treatment outcomes.

## Key findings

- 18% of patients switched from unilateral to bitemporal ECT, with remission rates increasing from 40% to 55%.
- Patients requiring switching had more prior manic episodes and higher antipsychotic use.
- Clozapine use and ECT charge increased during bitemporal sessions in the switched subgroup.

## Abstract

Electroconvulsive therapy (ECT) remains the most effective treatment for many patients with severe and/or resistant psychiatric disorders. Right unilateral (RUL) ECT, particularly when administered with titration and ultrabrief pulses, provides cognitive advantages compared with bitemporal (BT) ECT without compromising efficacy. However, some patients fail to improve and require switching to BT ECT. The present study aims to evaluate variables associated with efficacy and tolerability during RUL ECT and, when needed, after switching to BT ECT, aiming to identify factors linked to better outcomes with each placement.

A retrospective review was conducted on 58 adult inpatients treated with RUL ECT. Patients without improvement after 4–6 sessions could be switched to BT ECT. Demographic, clinical, pharmacological, and electric seizure-related data were collected. Treatment response was classified as total, partial, or none. Tolerability was assessed based on common side effects. Group comparisons were performed between RUL and BT ECT periods, and between unswitched and switched patients. Supplementary analysis was conducted to assess the relationship between efficacy/tolerability and the studied variables.

Of the patients who began with RUL ECT, 18 (31%) were switched to BT ECT. Remission occurred in 40% with RUL ECT and reached 55% cumulatively after BT ECT. Adverse effect rates were comparable between groups. Compared to patients who continued with the RUL ECT, those requiring switching had more prior manic episodes (p < 0.05), higher current antipsychotic use (p < 0.05), and a tendency for ECT to be indicated more often for severity than for treatment resistance (p < 0.10). Within the switched subgroup, clozapine use and ECT charge increased during BT sessions compared to the RUL course (p < 0.05).

Initiating treatment with RUL ECT and transitioning to BT ECT when necessary offers a pragmatic balance between tolerability and efficacy. Certain clinical variables may guide clinicians in anticipating the need for switching from a RUL to a BT setup.