Lithium, red blood cell choline and clinical state. A prospective study in manic-depressive patients.

Red blood cell (RBC) choline and ergothioneine levels were measured after repeated sampling of bipolar manic-depressive patients over 11 months of lithium maintenance. In addition, blood levels were measured in healthy volunteers, newly hospitalised lithium-free patients and from patients prior to, and after, initiating lithium. RBC choline levels did not differ between normal volunteers and newly admitted lithium-free patients with either mania or depression. After 4 weeks of lithium treatment RBC choline levels increased 6-fold, whereas the levels of the closely related compound ergothioneine did not change. Significant changes in mood during lithium maintenance were not accompanied by changes in RBC choline levels. These data indicate that lithium produced a specific accumulation of choline in erythrocytes. However the increased levels appear to be unrelated to clinical state and do not distinguish lithium responders from non-responders