Lunar phase cycle and psychiatric hospital emergency visits, inpatient admissions and aggressive behavior.

Introduction: We examined the correlation between lunar cycles and the number of psychiatric emergency visits, patients' gender, aggressive behavior, need for inpatient admission, legal referral and need for involuntary chemical restraint in a period of one calendar year.

Method: Charts of all psychiatric emergency room patients were reviewed retrospectively. Arabic calendar lunar months were divided based on three different models: Two 15 days sections, three 10 days, and six 5 days parts in the third model.

Results: 5431 patients were seen in the psychiatric emergency service (PES) during a one year period. We did not find a relationship between the visit time (day or night), gender, and legal referral in relation to moon cycles. A higher number of visits during full moon period which was not statistically significant (P>0.05) was found. Highest frequency of inpatient admissions was discovered in the first and last parts of the three part model and in the first and last segments of the six part model followed by second and fifth parts (P-values: 0.000).

Conclusion: This study revealed a slight increase in number of visits to psychiatric emergency room during full moon periods. In addition a highly significant increase in the severity of illness and aggressive behaviors and agitation in the beginning and end of the moon cycles were noticed. Some of the underlying possible causes such as changes in intra/extracellular fluids, neural and endocrine cell functions, hemodynamic and biological responses and changes in social dynamics and support are discussed.