Does Lithium Help Reduce Suicide Risk?
Patients with bipolar disorder are less likely to attempt suicide if they are taking lithium carbonate (Eskalith®, Glaxo-SmithKline; Lithobid®, Solvay) rather than divalproex sodium (Depakote tablet, Abbott), the most commonly prescribed mood-stabilizing drug in the U.S. Researchers who analyzed data from 20,638 patients in two managed care organizations in California found that divalproex was associated with 1.5 to three times more suicide attempts or deaths than lithium was.
After the researchers adjusted for age, sex, comorbid conditions, and the use of other psychotropic drugs, the risk of suicide death was found to be 2.7 times higher with generic divalproex than with lithium. The difference in risk was consistent across all outcome measures: suicide attempts ending in death, suicide attempts resulting in hospitalization, and suicide attempts diagnosed in the emergency department.
The mechanism by which lithium might help prevent suicide attempts is unclear, although it has been shown to reduce aggressive and impulsive behavior. Suicide is associated with reduced functional capacity of central serotonin systems, and long-term lithium treatment enhances serotonin turnover.
To their knowledge, the researchers say that this is the first study comparing the two drugs and their associations with suicide. They suggest that lithium might be getting an undeserved bad reputation; it has fallen out of favor over the years, because younger clinicians prefer newer, better-publicized drugs. Despite these findings, though, clinicians should exercise caution before deciding to stop prescribing mood stabilizers.
