Psychiatry Research, 4253-63 Elsevier 53 CSF Chromogranin A-like lmmunoreactivity in Schizophrenia: Relationships With REM Latency and Slow Wave Sleep Daniel P. van Kammen, Daniel T. O’Connor, Thomas C. Neylan, Andrew Mouton, John A. Gurklis, Mark W. Gilbertson, and Jeffrey L. Peters Received August 12. 1991; revised version received February 10, 1992; accepted March I, 1992. Abstract. Chromogranin A (CgA) is a calcium binding protein and a precursor of modulatory peptides in the brain. We measured CgA-like immunoreactivity (CgA-LI) in cerebrospinal fluid (CSF) in 15 male schizophrenic patients (diagnosed by DSMZZZ-R criteria) after 3 nights of polysomnography. Patients had been drug free for at least 33 days. Our earlier report that CSF CgA-LI in schizophrenic patients correlated significantly with negative symptoms and ventricle-brain ratios, which have been related to slow wave sleep, raised the possibility that CgA-LI might relate to slow wave sleep. CSF CgA-LI was significantly correlated with stage 4 sleep and rapid eye movement latency. Whether these positive relationships between CSF CgA-LI and electroencephalo- graphic sleep measures are specific for schizophrenia awaits further study. Key Words. Polysomnography, ventricle-brain ratios, stage 4 sleep, rapid eye movement sleep. Chromogranin A (CgA) is a calcium binding protein in the brain that is stored in the cytosol and is a precursor of modulatory peptides. Human CgA is a 49,918 dalton, acidic, monomeric protein (O’Connor and Frigon, 1984; Helman et al., 1988). CgA is found in the cerebral cortex, the bulbar medulla, and the hippocampus (Munoz, Daniel P. van Kammen, M.D., Ph.D., is Professor of Psychiatry, Western Psychiatric Institute and Clinic/The University of Pittsburgh School of Medicine, and Chief of Staff, Highland Drive Veterans Affairs Medical Center, Pittsburgh, PA. Daniel T. O’Connor, M.D., is Associate Professor of Medicine, University of California, San Diego, and Chief of the Division of Nephrology/Hypertension, Veterans Affairs Medical Center, San Diego, CA. Thomas C. Neylan, M.D., was Assistant Professor of Psychiatry, Western Psychiatric Institute and Clinic/The University of Pittsburgh School of Medicine, and Staff Psychiatrist, Highland Drive Veterans Affairs Medical Center, Pittsburgh, PA; he is now at Pacific Presbyterian Psychiatric Institute, San Francisco, CA. Andrew Mouton, Ph.D., was Staff Psychologist, Highland Drive Veterans Affairs Medical Center, Pittsburgh, PA, and is presently at the Veterans Affairs Lakeside Hospital, Chicago, IL. John A. Gurklis, M.D., is Assistant Professor, Western Psychiatric Institute and Clinic/The University of Pittsburgh School of Medicine, and Staff Psychiatrist, Highland Drive Veterans Affairs Medical Center, Pittsburgh, PA. Mark W. Gilbertson, Ph.D., is Assistant Professor of Psychiatry, Western Psychiatric Institute and Clinic/The University of Pittsburgh School of Medicine, and Staff Psychologist, Highland Drive Veterans Affairs Medical Center, Pittsburgh, PA. Jeffrey Peters, M.D., is Assistant Professor of Psychiatry, Western Psychiatric Institute and Clinic/The University of Pittsburgh School of Medicine, and Chief of Psychiatry Service, Highland Drive Veterans Affairs Medical Center, Pittsburgh, PA. (Reprint requests to Dr. D.P. van Kammen, Chief of Staff, Highland Drive VAMC, Pittsburgh, PA 15206, USA.) 01651781/92/$05.00 1992 Elsevier Scientific Publishers Ireland Ltd.