A link between lunar phase and medically unexplained stroke symptoms: An unearthly influence?

Abstract

Objective Lunar effects on human behaviour and health have been postulated for centuries; associations between phase of the moon and both vascular and psychiatric disease have been reported. We hypothesised that admission with medically unexplained stroke symptoms would be influenced by lunar cycle. Methods All admissions to the Western Infirmary Acute Stroke Unit are recorded in a comprehensive database. We analysed admissions between January 1, 1993, and September 30, 2006 (inclusive). Association between admission rate, phase of the moon, and a series of other culturally significant dates was calculated using chi-square testing. Results There were 7219 admissions during the study period, comprising 167 complete lunar cycles. Stroke admissions were evenly spread throughout lunar phases ( P=.72). Admission with medically unexplained stroke symptoms was significantly increased during full moon phases ( P=.023). There was no variation in admission rates during other significant dates. Conclusion There was a statistically significant association between admission to the acute stroke unit with a diagnosis of medically unexplained stroke symptoms and lunar phase. The reasons for this observed variation remain elusive; our data do not support a convincing biological or psychosocial aetiology.