When treating severe depression with electroconvulsive therapy (ECT), using stronger electric charges on just one side of the brain is just as effective as conventional protocols, which call for electrodes to be placed on either side of the head. Placing both electrodes on one side – called unilateral ECT, in fact may be advantageous because it produces fewer side effects, according to a new, randomized trial published February 19th in The American Journal of Psychiatry.

ECT, which is most often used in patients who have not responded to standard therapies, involves delivering small electric currents to the brain through the scalp while the patient is under general anesthesia. The electric currents induce a brief seizure across the brain, causing changes in brain chemistry that can quickly alleviate depression symptoms.

Although ECT is an effective treatment for severe depression, it’s often used as a late treatment – or even a “last resort” - because it can also bring cognitive side effects such as memory problems. To reduce the side effects as much as possible, researchers have investigated various setups involving different doses of electricity, treatment frequencies and placements of electrodes on the scalp. Although results have been mixed, previous studies have suggested that using ECT on only the right side of the brain (unilateral ECT) may produce fewer side effects than ECT on both sides of the brain (bitemporal ECT). However, for unilateral ECT to be as effective as bitemporal ECT, a higher dose of electricity is required.

In the new study, a team of researchers led by Declan M. McLoughlin, Ph.D, a 2003 NARSAD Independent Investigator grantee at Trinity College Dublin, Ireland, aimed to assess the effectiveness and side effects of two different setups in real-world practice. They compared twice-weekly ECT on both sides of the brain with high-dose ECT on just one side of the brain.

During routine practice, 138 patients were randomly assigned into either the standard bitemporal ECT group or the high-dose unilateral ECT group. The results showed that patients in both groups responded similarly. After finishing the treatment course, patients’ scores on standard depression questionnaires suggested that high-dose unilateral ECT was “not any less effective” than bitemporal ECT. Moreover, patients in the unilateral ECT group had a quicker recovery from typical disorientation experienced right after the treatment session. Also, compared with unilateral ECT, bitemporal ECT was associated with more memory problems that persisted for 6 months.

The findings suggest that high-dose unilateral ECT can be considered as the preferred option for treating depression, say the scientists, adding that further research is required to investigate other modifications to ECT to maintain its effectiveness while minimizing the side effects.

Takeaway: To reduce the side effects of electroconvulsive therapy (ECT), clinicians may consider using a modified protocol that involves using higher charges, applied only to one side of the brain.