Folate deficiency, anticonvulsant drugs, and psychiatric morbidity.

The folic acid (FOA) level was determined in serum and erythrocytes in 100 epileptic patients and 100 control patients using a luminescence assay. A lowered FOA concentration in serum, erythrocytes, or both was observed in 15% of the epileptic patients and in 2% of the control group. In the epileptic patients, the FOA in the serum and in the erythrocytes was significantly lower than that in the control group. Patients receiving carbamazepine monotherapy had a significantly lower FOA level in the erythrocytes than did patients receiving phenytoin monotherapy. The FOA level showed a negative correlation to the duration of epilepsy. None of the patients with lowered FOA had a normal mental status. The course of the supplementation treatment with 5 mg folinic acid (or FOA) of four patients with FOA deficiency could be monitored psychopathometrically. All four patients showed an improvement in their well-being and the majority of measured variables of the cognitive performance.