Koizumi T, et al. - In order to determine the possible circadian pattern of psychotic symptoms in patients with schizophrenia, which could be reflected on the dosing schedule/regimen (ie chrono-pharmacology), researchers investigated 49 with schizophrenia (ICD-10) who reported auditory hallucination and recieved monotherapy with risperidone, olanzapine or paliperidone for at least two weeks. They provided a diary to the subjects and asked them to record the time and duration of auditory hallucinations during the eight time periods, as well as the times of medication doses and sleep. Patients reported auditory hallucinations were most frequent and lasted the longest duration in the period of 18:00–21:00 (75.5% (37/49), and 1.37 ± 1.67 h) despite a less than 2% difference in D2 receptor occupancy between the peak and trough, signifying stable drug delivery. Given the stability of the dopamine D2 receptor blockade by antipsychotics, the identified nocturnal circadian pattern may indicate intrinsic dopaminergic variation or normally quieter environments at night. Consideration could be given to these circadian patterns to devise individualized treatment approach in the context of “chrono-pharmacology” for patients with schizophrenia.