Biochemical markers in the study of clinical effects and extrapyramidal side effects of neuroleptics.

Neuroleptic treatment was instituted in 20 female schizophrenic patients, who had not received neuroleptics for at least the preceding 3 months. Both the therapeutic response to neuroleptics and the development of parkinsonian side effects were monitored in these patients. In addition, plasma dopamine-beta-hydroxylase (DBH) and platelet monoamine oxidase (MAO) activities were measured. None of the neuroleptic responders developed parkinsonian symptoms. During the course of the 28-day treatment, there was a significant decrease in platelet MAO activity. There was a tendency for responders without parkinsonian symptoms to have lower plasma DBH activity than did nonresponders with parkinsonian symptoms.