Lithium and suicide in mood disorders: Updated meta-review of the scientific literature.

OBJECTIVES: Suicide and suicidal behaviour are increased in mood disorders, particularly bipolar disorders. Observational studies and small randomized controlled trials (RCTs) support the idea that taking lithium is associated with a reduction in these rates. This paper aims to review the best evidence for the effect of lithium on rates of suicide and self harm.
METHODS: We searched PubMed, PsycINFO, and the Cochrane Library systematically for systematic reviews and meta-analyses of RCTs of lithium and suicide and self harm published between January 1980 and June 2017. In the case of multiple publications on the same topic, only the most recent or most comprehensive review was considered.
RESULTS: A large number of reviews were identified, but only 16 publications were systematic reviews. Of these, three systematic reviews of lithium and suicide rates and one of lithium and self harm confined only to RCTs were identified. Despite some methodological concerns and heterogeneity in terms of participants, diagnoses, comparators, durations, and phase of illness, the evidence to date is overwhelmingly in favour of lithium as an antisuicidal agent, even balanced against any potential disadvantages of its use in regular clinical practice.
CONCLUSIONS: The anti-suicidal effects of lithium have been consistently reported over the past 40 years. The most robust evidence comes from RCTs, but these results are also discussed in the context of the difficulties in conducting high quality studies in this area, and the supporting evidence that observational and non-randomized studies can also provide. Given this evidence, however, the use of lithium is still underrepresented in clinical practice and should be incorporated more assertively into current guidelines.