This is the conclusion reached by a team of researchers directed by Professor Genevive Belleville of Universite Laval's School of Psychology after having examined the relationship between the moon's phases and the number of patients who show up at hospital emergency rooms experiencing psychological problems.

Details on the study can be found on the website of the scientific journal General Hospital Psychiatry.

To determine whether the widespread belief linking the moon to mental health problems was true, researchers evaluated patients who visited emergency rooms at Montreal's Sacre-Coeur Hospital and Hotel-Dieu de Levis between March 2005 and April 2008. They focused specifically on 771 individuals who showed up at the emergency room with chest pains for which no medical cause could be determined.

Psychological evaluations revealed that a sizeable number of these patients suffered from panic attacks, anxiety and mood disorders, or suicidal thoughts.

Using lunar calendars, the researchers determined the moon phase in which each of these visits occurred. The results of their analyses revealed no link between the incidence of psychological problems and the four lunar phases. There was one exception, however; anxiety disorders were 32% less frequent during the last lunar quarter. "This may be coincidental or due to factors we did not take into account," suggested Genevive Belleville. "But one thing is certain: we observed no full-moon or new-moon effect on psychological problems."

This study's conclusions run contrary to what many believe, including 80% of nurses and 64% of doctors who are convinced that the lunar cycle affects patients' mental health. "We hope our results will encourage health professionals to put that idea to rest," said Dr. Belleville. "Otherwise, this misperception could, on the one hand, color their judgment during the full moon phase; or, on the other hand, make them less attentive to psychological problems that surface during the remainder of the month."
In addition to Genevive Belleville, the study was coauthored by Guillaume Foldes-Busque, Melanie Dixon, Evelyne Marquis-Pelletier, and Sarah Barbeau from Universite Laval's School of Psychology; Julien Poitras and Richard Fleet from Universite Laval's Faculty of Medicine; Jean-Marc Chauny and Jean Diodati from Universite de Montral; and Andr Marchand from UQAM.