The study's conclusions run contrary to what many believe, including 80 percent of nurses and 64 percent of doctors who are convinced the lunar cycle affects patients' mental health.
Professor Genevieve Belleville of Universite Laval's School of Psychology and colleagues examined 771 individuals who showed up at the emergency room with chest pains for which no medical cause could be determined.
Psychological evaluations revealed a sizeable number of these patients suffered from panic attacks, anxiety and mood disorders, or suicidal thoughts, Belleville said.
Using lunar calendars, the researchers determined the moon phase in which each of the emergency room visits occurred.
The study, published in the journal General Hospital Psychiatry, said the analyses revealed no link among the incidence of psychological problems and the four lunar phases.
However, there was one exception. Anxiety disorders were 32 percent less frequent during the last lunar quarter.
"This may be coincidental or due to factors we did not take into account," Belleville said in a statement. "But one thing is certain: We observed no full-moon or new-moon effect on psychological problems."