Neurologic factors predict a favorable valproate response in bipolar and schizoaffective disorders.

The hypothesis that neurologic factors influence the response to valproate (divalproex sodium) in bipolar and schizoaffective disorders was tested. In 115 predominantly lithium-refractory inpatients, neurologic findings were recorded, and blind raters assessed valproate response from the medical record. Patients with a seizure history were much more likely to have a robust response to valproate (70%), when compared with patients without such history (34.6%). History of head injury and abnormal electroencephalographic findings also tended to be more common in those patients with good response. Overall, the group of patients with any neurologic abnormality exhibited a significantly higher rate of good response to valproate (43.6%) than did the neurologically normal group (24.3%). Bipolar or schizoaffective patients with abnormal neurologic features may represent a distinct subtype of illness and appear to be good candidates for valproate therapy.