Is it the moon? Effects of the lunar cycle on psychiatric admissions, discharges and length of stay

BACKGROUND: There is an ongoing debate concerning the connection between lunar cycle and psychiatric illness. AIMS OF THE STUDY: The purpose of the present study was to evaluate the rates of admission to and discharge from psychiatric inpatient treatment, as well as the length of stay, in relation to the lunar cycle, including 20 different categories of phases of the moon. METHODS: The data of 17,966 cases of people treated in an inpatient setting were analysed. Routine clinical data and data about admission and discharge were used. The lunar calendar was obtained from the website of the US Naval Observatory and was used to calculate the dates of the full moon according to the geographic location of the clinics. The clinics are located in the Canton Grisons in Switzerland. The following phases of the moon throughout the lunar cycle were defined: (a) full moon, (b) quarter waxing moon, (c) new moon, and (d) quarter waning moon. In addition, we coded one day and two days preceding every lunar phase as well as the two days following the respective phases of the moon. RESULTS: The lunar cycles showed no connection with either admission or discharge rates of psychiatric inpatients, nor was there a relationship with the length of stay. CONCLUSIONS: Despite the widespread belief that the moon impacts peoples’ mental health and subsequently psychiatric treatment, this study provides no evidence that our celestial neighbour influences our mental well-being.