This is a longitudinal double blind, 2- 5 year study of the clinical, neuroendocrine and biochemical response to clozapine (CLOZ) and haloperidol (HAL) in a group of "first episode" schizophrenic (RDC) patients. Within the protocol, we compare the differential effects of the two drugs over the short term (12 weeks) and the long-term (2-5 years); we evaluate the relationship between change in prolactin level and clinical response of the patients; and we search for biochemical predictors and correlates of clinical response. To achieve the study aims, we employ a drug-washout period, a 12-week acute treatment period; and an 88 - 260 week follow-up period.
