Effect of lithium on leukocytes: a two-year follow-up.

Leukocytosis is a common finding in patients given lithium salts, but few studies have addressed the possibility of persistent leukocyte elevation during long-term lithium therapy. We followed leukocyte counts in 32 manic-depressive patients over a 1-year period and in 25 over a 2-year period of lithium therapy, after establishing prelithium leukocyte baselines. During the first few weeks, most patients showed significant increases, which persisted throughout the course of treatment. These findings indicate that lithium might play a role in the treatment of certain leukopenic conditions.