Behavioral Effects of Reducing the Daily Frequency of Phenothiazine Administration.

After an 11-day base line of behavioral observations, 24 chronic female schizophrenics were assigned to two groups matched for alertness. In the first treatment phase, the administration of phenothiazine medication of one group was switched from a multiple-dose schedule (three to four times per day) to a single daily administration, while the total dosage per day was held constant. The second group continued on a multiple administration schedule for 11 days and then was switched to a single daily dosage. A multivariate analysis of variance showed that there was no overall effect (positive or negative) due to the schedule change; however, preplanned t tests showed transitory decreases in nonfunctional behavior. The results are discussed in terms of implications for the administration of phenothiazines and the experimental analysis of drug effects.