"A large study that made use of a Swedish health database has shown that lithium reduces suicide rates in bipolar disorder. The study by researcher Jie Song and colleagues was published in the American Journal of Psychiatry in 2017.
The study included eight years of data from 51,535 people with bipolar disorder. During that time, there were 10,648 suicide-related events recorded, such as suicide attempts or completed suicides. The researchers compared suicide rates when patients were taking lithium to rates when they were off the drug, and found that lithium reduced attempted or completed suicide by 14%. Song and colleagues also looked at suicide rates for people taking valproate, and found that these were no better than when patients were off valproate, implying that treatment alone is not enough to reduce the suicide rate and the benefit is specific to lithium use.
Song and colleagues estimate that 12% of the suicide-related events among the patients included in the study might have been avoided if the patients had taken lithium for the entire study period. While there are other clinical considerations to make when selecting an appropriate treatment for a given patient, the researchers suggest that lithium treatment should be considered for patients with bipolar disorder who have expressed suicidal intentions or who are otherwise at risk for suicide."