Association between pulse width and clinical response to electroconvulsive therapy.

BACKGROUND

The default pulse width setting on a commonly used electroconvulsive therapy (ECT) device, 0.5 ms (ms), is untested against the proven effectiveness of conventional 1.0-1.5 ms brief pulse widths.

METHODS

We examined the association between pulse width and clinical response using registry data from 87 centres in the United Kingdom and Republic of Ireland in patients (N = 1956) receiving consecutive acute courses of ECT ending during 2023 for any clinical indication. The outcome was clinical response, defined as an end-of-treatment Clinical Global Impression‒Improvement score of 1 or 2.

RESULTS

Mean age was 61.6 years (SD, 16.3), 66.3 % were female, 84.2 % were treated for depressive episode, and 86.5 % received bilateral ECT. In a multivariable logistic regression analysis of all diagnostic categories, 0.5 ms (adjusted odds ratio 0.64; 95 % CI, 0.50-0.82; p < .001) and 0.25-0.3 ms (adjusted odds ratio 0.56; 95 % CI, 0.38-0.82; p = .003) pulse widths were associated with significantly lower odds of response compared to 1.0 ms. Predicted probabilities of response were 73.4 % (95 % CI, 69.4 %-77.3 %) for 1.0 ms, 64.1 % (95 % CI, 61.4 %-66.8 %) for 0.5 ms, and 61.0 % (95 % CI, 53.8 %-68.3 %) for 0.25-0.3 ms. A subgroup analysis of unipolar or bipolar depressive episodes likewise showed significantly reduced odds of response with both 0.5 ms and 0.25-0.3 ms.

CONCLUSION

This study demonstrated a previously unreported association between 0.5 ms pulse width and reduced ECT response. Unless cognitive sparing is paramount in an individual case, 1.0 ms ECT should be used as standard.