The results showed a steep drop in brain activity related to deep sleep. The volunteers, 33 of them divided into two age groups, took five minutes longer to fall asleep and their sleep duration was reduced by 20 minutes, according to the research. Their bodies also produced less melatonin, a hormone known to regulate sleep.
"I was very skeptical until we saw the data," said Cajochen, the lead researcher on the study. "We have to follow it up."
Cajochen said he didn't "dare publish it right away because the issue is very controversial. Until now there hasn't been a peer-reviewed study like this." Cajochen wants other researchers to confirm his team's findings. An ideal study would look at patients over the full lunar cycle, which is 29.5 days, he said.
Earlier studies have provided promising yet ultimately inconclusive glimpses of the moon's impact on humans and animals.
The British Medical Journal published two articles on dog bites and the full moon in its Dec. 23, 2000 edition. One showed the number of people bitten by animals "accelerated sharply" at the time of a full moon based on 1,621 patients seen in the emergency room at Bradford Royal Infirmary in Bradford, England, over a two-year period. The other, based on admission rates for dog bites over a one-year period at public hospitals in Australia, showed no moon impact.
Data on crime has been equally mixed. Based on police records and emergency room visits in Dade County, Fla., over a five-year period, researchers found a "significant clustering of cases" of homicides and aggravated assaults around the full moon, according to a study published in The Journal of Clinical Psychiatry in May 1978. Another study looking at police records of arrests in Decatur, Ill., between 1967 and 1973 found no relationship between lunar activity and violence.