Depression and cerebrospinal fluid citrate.

In relation to studies of calcium metabolism in manic-melancholic patients, the calcium binding metabolite citrate was analyzed in cerebrospinal fluid from 163 psychiatric and non-psychiatric patients. Patients with symptoms of depression, irrespective of whether the origin of the depression was endogenous or exogenous, had significantly higher cerebrospinal fluid citrate concentrations than non-psychiatric patients. Manic patients and other psychiatric patients without symptoms of depression were not significantly different from the non-psychiatric patients. When the mood was normalized after various treatments, cerebrospinal fluid citrate decreased in all groups of depressed patients.