The effects of ceruletide in schizophrenia.

Eight neuroleptic-resistant schizophrenic patients were treated with ceruletide diethylamine, a cholecystokininlike peptide, in a placebo-controlled, double-blind, cross-over study. Ceruletide or placebo was administered intramuscularly twice a day for four consecutive days while patients received a constant dose of fluphenazine hydrochloride. Cholecystokinin octapeptide was also administered to four different schizophrenic patients in a double-blind, cross-over study. Cholecystokinin or placebo was administered as a slow intravenous infusion daily for four days. There were no changes in either the positive or negative symptoms of schizophrenia between the periods of placebo, ceruletide, or cholecystokinin administration. Furthermore, there was no tendency for the patients' conditions to either improve or worsen during the course of ceruletide or cholecystokinin treatment. In contrast to previous reports from uncontrolled studies, cholecystokininlike peptides appear to be devoid of antipsychotic properties when administered parenterally.