Does lunar synodic cycle affect the rates of psychiatric hospitalizations and sentinel events?

The lunar synodic cycle is often believed to be associated with psychiatric emergencies and exacerbation in various countries, including India. However, the scientific literature regarding this matter is inconclusive. We aimed to evaluate the relationship between lunar cycle phase and admission rates plus occurrence of sentinel events in the psychiatric ward of a tertiary care general hospital in India. All admissions and transfer-ins (N = 780) to the Department of Psychiatry between August 1st, 2016 and July 31st, 2017 were evaluated from hospital records by a blinded author to obtain sentinel events, like requirement of physical restraint (PR) and chemical restraint (CR), occurring on full moon days (FM), new moon days (NM), and control days (CD). Statistical analysis was done by comparison of proportions. Significant positive differences were found when CR applied exclusively [p = .0008] on FM and NM days, and its frequency [p < .0001] in comparison to CD. Frequencies of parenteral [p = .0001] and per oral [p = .0064] modes of CR applied on FM and NM days showed significant positive results when compared with CD. Use of all restraints (PR plus CR) [p = .0017] and their frequencies [p < .0001] on FM and NM days were also positively significant. Sentinel events, such as use of restraints, especially chemical ones, in psychiatry in-patients are significantly more common during full moon and new moon phases.