Disturbed circadian rest-activity cycles in schizophrenia patients: An effect of drugs?

The circadian rest-activity cycle of schizophrenia patients stabilized for more than a year on monotherapy with a "classical" neuroleptic (haloperidol, flupentixol) or with the atypical neuroleptic clozapine was documented by continuous activity monitoring for 3-7 weeks. In this pilot study, the three patients treated with clozapine had remarkably highly ordered rest-activity cycles, whereas the four patients on classical neuroleptics had minor to major circadian rhythm abnormalities. This is the first documentation of circadian rest-activity cycle disturbances in schizophrenia related to class of drug.