Reduced cholecystokinin immunoreactivity in the cerebrospinal fluid of patients with psychiatric disorders.

The close relationship of cholecystokinin peptides with some of the dopamine pathways and the limbic system suggests a putative role for these peptides in the pathophysiology of neuropsychiatric disorders such as Parkinson's disease, manic-depression and schizophrenia. By use of radioimmunoassay, we report a significant decrease in cholecystokinin-immunoreactivity in the cerebrospinal fluid of patients with bipolar manic-depression and untreated schizophrenia in comparison to control subjects.