Plasma biopterin levels of patients with affective disorders.

The plasma biopterin levels of 13 patients with affective disorders were measured both in the symptomatic phase and in the remission phase, and under no influence of psychotropic drugs except lithium and/or carbamazepine by high-performance liquid chromatography with fluorescence detection, and were compared with those of normal controls. The biopterin levels of patients in the symptomatic phase were elevated significantly as compared with those of normal controls, and the elevation tended to be more pronounced in the hypomanic phase than in the depressive phase. In contrast, the biopterin levels of patients in remission were not different from those of normal controls.