title: Exploring environmental cycles in psychiatric patients.
abstract: The daily psychiatric inpatient population at a large medical center recorded over a two-year period and consisting of 11,864 inpatient days was analyzed for circannual (365-day) and synodic (29.53-day) cycles. A highly significant circannual cycle, in which the population peaks in early February, was found. This cycle was compared to seasonal cycles of photoperiod, sunlight, and temperature and was found to be highly correlated with each. The best correlation was between patient population and photoperiod during the previous month. A significant synodic (lunar) cycle, with a peak in patient census occurring at the last quarter moon, was also found.
authors.forename: J L
authors.initials: JL
authors.lastname: Temte
mesh_terms: D004777:Environment; D006801:Humans; D007297:Inpatients / Q000523:psychology; D001523:Mental Disorders / Q000523:psychology*; D010507:Periodicity; D011567:Psychiatric Department, Hospital / Q000706:statistics & numerical data*; D012044:Regression Analysis; D012621:Seasons; D013472:Sunlight; D013696:Temperature; D013997:Time Factors; D014922:Wisconsin