Genetic Variants Predict Lithium Response in Bipolar Disorder

Genetic variations on a stretch of chromosome may predict responsiveness among patients with bipolar disorder to the mood stabilizing drug lithium (multiple brands), a genome-wide analysis by an international consortium shows.

The study, led by Francis J. McMahon, MD, National Institute of Mental Health, Bethesda, Maryland, showed that four single-nucleotide polymorphisms (SNPs) on chromosome 21 were linked to lithium response. A separate analysis indicated that carriers have an almost fourfold reduction in relapse rates.

Although lithium is a first-line treatment for bipolar disorder, previous studies have indicated that individual patient responses are variable, with at least 30% of patients having no clinical response.

“This finding could have important implications for our understanding of lithium’s mechanism of action in bipolar disorder, although replication in independent samples is needed,” the team says.