Ceruletide for schizophrenia: a double-blind study.

Ceruletide, an analog of cholecystokinin (CCK), has been reported to have neuroleptic-like activity in mice, and, in three open studies, to benefit schizophrenic patients. This study evaluated ceruletide in schizophrenia using a double-blind design. Subjects were 17 chronic schizophrenics with residual symptoms following stabilization with neuroleptics. Patients randomly received two injections, 1 week apart, of either ceruletide (0.6 microgram/kg im) or placebo, while continuing neuroleptics; this regimen was found helpful in earlier studies. Evaluation included ratings of 29 variables related to prognosis in schizophrenia (e.g., age, number of previous hospitalizations), regular BPRSs and SCL-90s, and psychiatrist, patient, and relative ratings of global improvement. Results showed few significant differences between ceruletide and placebo, with exceptions as likely to favor placebo as ceruletide. Among the patients on ceruletide, no predictors of benefit were found. Possible reasons for the negative results are discussed.