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 2 groups matched for alertness. In the first treatment phase, the administration of phenothiazine medication of 1 group was switched from a multiple dose schedule (3 to 4 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.