Study designs of evaluations included in the review
The review included randomised, unconfounded controlled trials for comparisons of ECT with no ECT, ECT versus pharmacotherapy, or different forms of ETC. Non randomised studies investigating mortality after ECT, and case-control neuroimaging and post-mortem studies looking at the possibility of structural brain changes after ECT, were also identified.
Specific interventions included in the review
The interventions included ETC. ECT versus pharmacotherapy or studies of different forms of ECT, such as bilateral ECT, unipolar ECT and high- and low-dose ECT, were eligible.
Participants included in the review
Participants with a diagnosis of depressive illness were included in the review. Participant subgroups were identified by clinical or demographic factors: psychotic depression, retarded depression, and the effect of age, treatment resistance, gender and severity of depression.
Outcomes assessed in the review
The primary outcome used to estimate the efficacy of ECT was the change in symptoms on a continuous depressive symptom scale at the end of the course of ETC.
Changes in depressive symptoms, cognitive functioning (especially memory functioning) and other outcomes such as premature discontinuation of ECT and mortality were assessed. The change in symptoms at 6 months' follow-up was also investigated.
How were decisions on the relevance of primary studies made?
Two reviewers independently checked the search results. Any disagreements were resolved by discussion within the study team.