Polysomnography, performed at the beginning of October 2007 under psychotropic treatment, showed light fragmented sleep, and actigraphy showed an irregular sleep-wake cycle, with abnormally raised nocturnal activity. Twenty-four hour urinary 6-sulfatoxymelatonin levels were barely detectable with absence of the typical 24-hour sleep-wake cycle. Treatment with controlled-release melatonin was started in October 2007. The patient's sleep rapidly stabilized, with restoration of a regular sleep-wake cycle and marked improvement of psychotic symptoms, permitting progressive withdrawal of psychotropic medication between January and April 2008. Further sleep analyses, performed in mid-November 2007, showed restoration of slow-wave sleep, with diminished sleep fragmentation, and actigraphy confirmed restoration of a normal sleep-wake cycle. Treatment with controlled-release melatonin was discontinued in 2009, and the patient remains medication- and symptom-free, with a stable sleep-wake cycle.