Lunar Cycles and Human Behavior

Article excerpt

The Problem

Your partner hands you the on-call pager and wishes you good luck. You wonder what he means until you realize that the night sky will be illuminated by a full moon. You wonder whether Shakespeare was right and whether you are in for it: "It is the very error of the moon; She comes more nearer earth than she was wont; And makes men mad ..." (Othello, Act 5, Scene 2).

The Question

Do lunar cycles affect human behavior?

The Analysis

We first searched the Cochrane Database of Systematic Reviews (www.cochrane.org/reviews) and found no reviews. We then searched Medline combining "lunar or moon" and "behavior."

The Evidence

The notion that stars and planets influence unusual or deviant human behavior can be traced to Roman times. Even among mental health professionals, there is a common belief that lunar cycles influence human behavior (J. Psychosoc. Nurs. Ment. Health Serv. 2000;38:29-34).

An early meta-analysis looked at data from 37 studies examining the relationship between phases of the moon and different types of "lunacy," including psychiatric admissions, psychiatric disturbances, crisis calls, suicides or self-harm, homicides, and other types of criminal activity (Psychol. Bull. 1985;972:286-306). The total number of psychiatric admissions looked at were 89,973 over 467 lunar cycles, 5,575 psychiatric disturbances over 477 cycles, 43,177 crisis calls over 148 cycles, 32,273 suicides or self-harm incidents over 343 cycles, 29,126 homicides over 599 cycles, and 535,836 criminal offenses over 229 cycles. The authors found that the phases of the moon accounted for no more than 1% of the variance in human behavior.

Scottish researchers looked at the correlation between 20,919 acts of self-injurious behavior in patients aged 16 or older over 222 lunar cycles (Psychol. Med. 1991;21:393-7). A sine-wave curve of self-injurious behavior was found, but without correlation to lunar cycle.

Spanish investigators looked at the association between motor vehicle crashes and lunar cycles (Percept. Mot. Skills 1993;77:371-6). A total of 4,835 accidents occurred over 48 lunar cycles. No relationship was found between lunar cycle and the number of accidents when analyzed for the entire period.

Psychologists in Massachusetts looked at the relationship between lunar cycles and the occurrence of psychiatric hospital admission of developmentally disabled adults (Psychol. Rep. 1994;75:1435-40). A total of 86 community-based, developmentally disabled adults were followed over 35 lunar cycles. No correlation was found between lunar cycles and admissions.

Researchers in a British seaside town followed 100 patients through 30 lunar cycles (J. Psychosoc. Nurs. Ment. Health Serv. 2000;38:29-34). When the study was conducted, the possibility of a lunar effect was not considered. …