Lithium in the prevention of suicidal behavior and all-cause mortality in patients with mood disorders: A systematic review of randomized trials

Objective: Observational studies suggest that long-term lithium treatment has a strong antisuicidal effect in mood disorders, but it is uncertain whether this association is a genuine therapeutic effect or is due to confounding factors in nonrandomized studies. The authors conducted a systematic review and meta-analysis of randomized trials to investigate the effect of lithium, compared to placebo and other active treatments, on the risk of suicide, deliberate self-harm, and all-cause mortality in patients with mood disorder. Method: The data source was the Cochrane Collaboration Depression, Anxiety and Neurosis Controlled Trials Register, incorporating results of searches of MEDLINE (1966-June 2002), EMBASE (1980-June 2002), CINAHL (1982-March 2001), PsycLIT (1974-June 2002), PSYNDEX (1977-October 1999), and LILACS (1982-March 2001). The Cochrane Central Register of Controlled Trials (CENTRAL) was searched with the term "lithium" for new records entered into the database from 1999 to 2003. Studies selected included randomized, controlled trials comparing lithium with placebo or all other compounds used in long-term treatment for mood disorders (unipolar depression, bipolar disorder, schizoaffective disorder, dysthymia, and rapid cycling, diagnosed according to DSM or ICD criteria). Of 727 references identified in the search, 52 articles were marked as possibly relevant on the basis of the abstract, and 32 randomized, controlled trials were eligible for inclusion in the review. Two independent reviewers extracted the data, and disagreements were resolved by consensus with a third reviewer. Methodological quality was assessed according to the criteria of the Cochrane Collaboration. When the outcomes of interest were not reported, an attempt was made to obtain the required data from the original authors. Results: In 32 trials, 1,389 patients were randomly assigned to receive lithium and 2,069 to receive other compounds. Patients who received lithium were less likely to die by suicide (data from seven trials; two versus 11 suicides; odds ratio=0.26; 95% confidence interval [CI]=0.09-0.77). The composite measure of suicide plus deliberate self-harm was also lower in patients who received lithium (odds ratio=0.21; 95% CI=0.08-0.50). There were fewer deaths overall in patients who received lithium (data from 11 trials; nine versus 22 deaths; odds ratio=0.42, 95% CI=0.21-0.87). Conclusions: Lithium is effective in the prevention of suicide, deliberate self-harm, and death from all causes in patients with mood disorders.