Erythrocyte choline concentration in bipolar disorder: a predictor of clinical course and medication response

Erythrocyte choline concentrations were measured in hospitalized patients with bipolar disorder, manic phase, and control subjects. There was a significant elevation in mean erythrocyte choline in the patients with mania. This elevation in erythrocyte choline was due to a subgroup of patients with especially high values. Significant clinical differences were apparent between the patients with "high" and those with "low" erythrocyte choline concentrations. The subgroup of manic patients with elevated erythrocyte choline had a more severe illness at admission, a worse outcome at discharge, and required significantly more neuroleptic during hospitalization than their low choline counterparts; that is, they were less likely to respond well to lithium alone. Furthermore, the bipolar patients with low erythrocyte choline concentrations, as a whole, had more than four times as many previous manic episodes than depressive episodes, while the patients with high choline values had approximately the same number of past manias and depressions. These results are discussed in light of the evidence implicating cholinergic neurotransmission in the pathophysiology of affective disorders. In addition, the design of future clinical studies of erythrocyte choline and its possible clinical utility are discussed.