Study designs of evaluations included in the review
The authors did not specify inclusion criteria relating to the study design, other than 'clinical trials'. They did, however, report whether the included studies were of a blinded or open design.
Specific interventions included in the review
Studies that used lithium as the primary treatment (of any duration) or permitted separate analysis of lithium-treated participants were eligible for inclusion in the review. The duration of the treatment ranged from one month to 70.8 months.
Participants included in the review
Studies of patients with major affective disorders were eligible for inclusion. Studies that either included single-sex samples not otherwise selected, or specified or permitted the determination of response rates for men and women separately, were also eligible for inclusion. All but one of the reports included in the review included data for both men and women. The patients included in the review had bipolar affective disorder (I and II, depressed and manic), or were mixed samples of patients with major affective disorders including recurrent major depression and bipolar disorder.
Outcomes assessed in the review
The outcome was response to treatment, as defined in each study.
How were decisions on the relevance of primary studies made?
The authors do not state how the papers were selected for the review, or how many of the reviewers performed the selection.