How long do people stay well after ECT versus ketamine? A review of 13 studies

The question

For people with depression that has not responded to standard treatments, how long does the benefit last before symptoms return after electroconvulsive therapy (ECT) compared with ketamine?

What they did

The authors searched eight research databases for studies reporting time-to-relapse in treatment-resistant depression. Thirteen studies met their criteria: 10 looked at ketamine or (es)ketamine and 3 looked at ECT. Twelve were randomised controlled trials and one was a retrospective chart review. Because the studies differed too much and no study directly compared the two treatments under their criteria, the results were described in words rather than combined statistically.

What they found

Both ECT and ketamine showed signs of lasting antidepressant effects, with ECT possibly linked to a longer period of remission. Higher doses, more frequent sessions and ongoing maintenance treatment with either ECT or ketamine appeared to extend the time before relapse. Continuing oral antidepressants alongside treatment appeared to extend it further. The authors concluded that no studies meeting their criteria directly compared time-to-relapse between the two, so no formal statistical comparison was possible.

The fine print

There were no head-to-head comparisons within the included studies, so any difference between ECT and ketamine is indirect and uncertain. The included studies varied widely in dosing and schedules, and some had small samples and short follow-up. Studies of depression with psychotic symptoms were excluded, which also removed some direct comparison studies and limits how broadly the findings apply. This summary is based on the abstract only.

What it means

Both ECT and ketamine can keep depression symptoms at bay for a time, and ongoing maintenance treatment seems to help, but the existing research is not good enough to say which one lasts longer.

Evidence grade: Low. A systematic review that could not pool the data statistically, so it relies on a narrative summary of 13 heterogeneous studies with varied doses, schedules and follow-up.

This summary is based on the study’s published abstract.