Dopamine-Beta-hydroxylase (DBH) has been measured in cerebrospinal fluid (CSF) from normal volunteers and neurological and psychiatric patients. The DBH levels in CSF from patients with diseases of the basal ganglia were not significantly different from normal volunteers. Among members of a family with dystonia, CSF DBH varied widely, was not related to the severity of the disease, and was not significantly different from normal DBH levels. When alcoholics were treated with disulfiram, there was no change in CSF DBH activity. Basal DBH activity was related to adverse drug reactions. Patients with lower DBH in the CSF were more susceptible to adverse (psychotic and other) reactions to disulfiram. These data are consistent with the known inhibitory effect of disulfiram on DBH in situ. DBH in CSF was also related to personality measures. The patients with low CSF DBH had elevated MMPI profiles, suggesting psychological vulnerability.