Erythrocyte choline concentrations in psychiatric disorders.

Erythrocyte choline has been used as a potential indirect measure of cholinergic function in the central nervous system (CNS). We review the literature and present some new data on erythrocyte choline concentrations in patients with neuropsychiatric disorders. Our data and most of the reviewed studies report modest elevations in mean erythrocyte choline values in patients with affective illnesses, psychoses, dementia, and other neuropsychiatric disorders when compared to controls. Within each disorder, the increased mean erythrocyte choline concentrations are due to subgroups of patients with especially high values. These subgroups of patients with elevated erythrocyte choline levels appear to have clinical characteristics that distinguish them from patients with normal choline values. Finally, the dramatic rise in erythrocyte choline concentration produced by lithium therapy is reviewed, and the implication of this effect, in particular, the possibility that pretreatment or posttreatment erythrocyte choline concentrations may predict response to lithium, is discussed.