Much Ado About the Full Moon. A Meta-Analysis of Lunar-Lunacy Research

Abstract

Data from 37 published and unpublished studies were combined in a meta-analysis that examined relations between phase of the moon, type of lunar cycle, sex, publication practices, geographical features (latitude, population density), and several types of lunacy, including mental hospital admissions, psychiatric disturbances, crisis calls, homicides, and other criminal offenses. Although a few statistically significant relations emerged, effect size estimates indicated that phases of the moon accounted for no more than 1% of the variance in activities usually termed lunacy. Alleged relations between phases of the moon and behavior can be traced to inappropriate analyses, a failure to take other (e.g., weekly) cycles into account, and a willingness to accept any departure from chance as evidence for a lunar effect. © 1985 American Psychological Association.