To the Editor.
—1Recently, Hökfelt et al1 postulated that an imbalance between cholecystokinin (CCK)-like peptides and dopamine in the mesolimbic dopamine system may be a cause of schizophrenia. Furthermore, they suggested that, when administered, CCK fragments may have beneficial effects on schizophrenia by reducing dopamine hyperactivity in the mesolimbic dopamine system. On the other hand, Zetler2-4 has demonstrated that CCK-8 and ceruletide (caerulein), a decapeptide chemically related to CCK-8, have neurolepticlike activity in mice. Interestingly, the central depressant effects were elicited by ceruletide in lower doses than by CCK-8. Ceruletide diethylamine is used clinically in radiologie examination of the gallbladder, biliary system, and digestive tract, and in the treatment of postoperative paralytic ileus, intestinal hypotonia, and atonia.5 We administered ceruletide to 20 chronic schizophrenic inpatients in whom neuroleptic therapy had been ineffective, to investigate the antipsychotic efficacy of CCK-like peptides.All the patients were receiving various neuroleptics during
Moroji T, Watanabe N, Aoki N, Itoh S. Antipsychotic Effects of Ceruletide (Caerulein) on Chronic Schizophrenia. Arch Gen Psychiatry. 1982;39(4):485–486. doi:10.1001/archpsyc.1982.04290040079011