Melatonin immunoreactivity in cerebrospinal fluid of schizophrenic patients and healthy controls.

Melatonin is produced in the pineal gland. Its involvement in various psychiatric and somatic diseases has been suggested. We investigated melatonin in cerebrospinal fluid of 16 healthy controls, 15 paranoid schizophrenics being treated with neuroleptics, and 13 unmedicated paranoid schizophrenics. There were no significant differences in melatonin concentrations among these three groups. No significant correlations were found between melatonin concentrations and various other biochemical substances such as noradrenalin, cyclic adenosine 3', 5'-monophosphate, prolactin, and cortisol. These negative results do not support the suggestion that melatonin is involved in the etiology of schizophrenia. However, other possibilities, e.g., a change of biological rhythms and its influence on other neuroendocrine functions, may be of importance.