DOES THE FULL MOON CHANGE OUR BEHAVIOUR?*
By Dr. Stephen Juan

The final 2009 issue of the Medical Journal of Australia contains a report on a study in an Australian hospital that has identified a spike in out-of-control "werewolf" patients when a full moon is out.  There were 91 emergency patients rated as having violent and acute behavioural disturbance at the Calvary Mater Newcastle hospital from August 2008 to July 2009.  Leonie Calver, a clinical research nurse in toxicology, said almost a quarter of the cases (23 per cent) occurred on a night of full moon and this was double the number for other lunar phases.  The patients all had to be sedated and physically restrained to protect themselves and others.  "Some of these patients attacked the staff like animals - biting, spitting and scratching," Ms Calver said.  "One might compare them with the werewolves of the past, who are said to have also appeared during the full moon."  Ms Calver said werewolf mythology included reports of people rubbing "magic ointment" onto their skin or inhaling vapours to induce the shirt-rending transformation from man to beast.  The main ingredients were belladonna and nightshade, she said, both substances that could produce delirium, hallucinations and delusion of bodily metamorphosis.  Ms Calver said it appeared the "modern day werewolf" preferred alcohol or illicit drugs, as more than 60 per cent of the patients reviewed in the study were under the influence.  "We don't know if it’s more fun to use drugs and alcohol under a full moon or if their behavioural disturbance is directly influenced by the moon," she said.  "Our findings support the premise that individuals with violent and acute behavioural disturbance are more likely to present to the emergency department during... full moon."

A full moon happens at least once every month. Sometimes, rarely, it happens twice a month.  Popular legend has it that the full moon brings out the worst in people: more violence, more suicides, more murders, more accidents, more aggression.  The influence of the moon and behaviour has been called "The Lunar Effect" or "The Transylvania Effect."  The belief that the full moon causes mental disorders and strange behaviour was widespread throughout Europe in the middle ages.  Even the word "lunacy" meaning "insanity" comes from the Latin word for "moon."

The belief that humans are somehow affected by the full moon is one of our civilization's oldest notions about the causes of behaviour.  Both Pliny the Elder (23-79 A.D.) and Plutarch (46-120 A.D.) wrote of the widespread nature of this belief.  Anthropologists report it as an extremely common notion throughout the belief systems of many non-Western societies.  Our traditional folklore is filled with such references, as is our popular culture today.  Personnel at psychiatric hospitals around the world have for many years claimed that patients are usually more difficult to manage during nights with a full moon.  The term "lunatic" is sustained in our language by the persistence of such reports.  We know that the full moon affects tides, plant growth, and many other physical and biological processes.  Women's menstruation, possibly hair and nail growth, and perhaps other aspects of human biology may be slightly influenced as well.  This is very controversial.  Statistically, more babies are born during the full moon than at any other time in the lunar cycle. Yet the reasons for this remain unclear.  Research on the possible effect of the full moon on erratic or violent behaviour has been inconclusive over the last two decades.

Possibly the most convincing evidence that lunar cycles affect violent behaviour comes from Dr. Arnold Lieber of the University of Miami School of Medicine. In his 1978 study, Dr. Lieber concluded that the occurrence of self-destructive acts is positively correlated with the full moon. It was then theorized that this must be due to some inherent "biological rhythm of human aggression".  Other studies hint at possible relationships, but fail to establish statistically significant correlations.

Still other studies have completely rejected the full moon as an influence on erratic or violent behaviour.  This has been the trend in the research for about fifteen years.  In one study, it was statistically demonstrated that the full moon has not affected the U.S. homicide or suicide rates.  In another study, it was shown that the phases of the moon did not alter the rate of disruptive behaviours of inmates at a U.S. psychiatric institution.  In an unusual twist, still another study found that the number of patients with violent injuries actually fell during the full moon.  This goes 180 degrees against the commonly-held view.  In this study, Drs Wendy Coates, Dietrich Jehle, and Eric Cottington from the Allegheny General Hospital in Pittsburgh reviewed all admissions for trauma over a period of one year at their hospital.  They found that of the 199 stabbing and shooting victims admitted, there were eight patients admitted on full moon days for every ten admitted on non-full moon days.  This led them to write, "we conclude that the belief in the deleterious effects of the full moon on major trauma is statistically unfounded."

According to LiveScience.com:

• The moon holds a mystical place in the history of human culture, so it is no wonder that many myths - from werewolves to induced lunacy to epileptic seizures - have built up regarding its supposed effects on us.
• "It must be a full moon," is a phrase heard whenever crazy things happen and is said by researchers to be muttered commonly by late-night cops, psychiatry staff and emergency room personnel.
• It's been a long time since the Big Cheese revealed any new secrets as important as this week's announcement that traces of water exist all across its surface. Coincidentally, a study this week found zero connection between the full moon and surgery outcomes.
• In fact a host of studies over the years have aimed at teasing out any statistical connection between the moon - particularly the full moon - and human biology or behaviour.  The majority of sound studies find no connection, while some have proved inconclusive, and many that purported to reveal connections turned out to involve flawed methods or have never been reproduced.  Reliable studies comparing the lunar phases to births, heart attacks, deaths, suicides, violence, psychiatric hospital admissions and epileptic seizures, among other things, have over and over again found little or no connection.
• One possible indirect link:  Before modern lighting, the light of a full moon have kept people up at night, leading to sleep deprivation that could have caused other psychological issues, according to one hypothesis that awaits data support.
• The moon, tides and you:
  • The human body is about 75 percent water, and so people often ask whether tides are at work inside us.
  • The moon and the sun combine to create tides in Earth's oceans (in fact the gravitational effect is so strong that our planet's crust is stretched daily by these same tidal effects).
  • But tides are large-scale events.  They occur because of the difference in gravitational effect on one side of an object (like Earth) compared to the other.  Here's how they work (full explanation of tides):
  • The ocean on the side of Earth facing the moon gets pulled toward the moon more than does the centre of the planet.  This creates a high tide. On the other side of the Earth, another high tide occurs, because the centre of Earth is being pulled toward the moon more than is the ocean on the far side.  The result essentially pulls the planet away from the ocean (a negative force that effectively lifts the ocean away from the planet).  However, there's no measurable difference in the moon's gravitational effect to one side of your body vs. the other.  Even in a large lake, tides are extremely minor.  On the Great Lakes, for example, tides never exceed 2 inches, according to the National Oceanic and Atmospheric Administration (NOAA), which adds, "These minor variations are masked by the greater fluctuations in lake levels produced by wind and barometric pressure changes. Consequently, the Great Lakes are considered to be essentially non-tidal."  This is not to say tides do not exist at smaller scales.  The effect of gravity diminishes with distance, but never goes away.  So in theory everything in the universe is tugging on everything else. However, "Researchers have calculated that a mother holding her baby exerts 12 million times the tide-raising force on the child than the moon does, simply by virtue of being closer," according to Straightdope.com, a Web site that applies logic and reason to myths and urban legends.  Consider also that tides in Earth's oceans happen twice every day as Earth spins on its axis every 24 hours, bringing the moon constantly up and down in the sky. If the moon's tugging affected the human body, one might presume we'd be off balance at least twice a day (and maybe we are).

Studies of full moon effects cover the following topics and come to the following conclusions:

Epilepsy:  A study in the journal Epilepsy & Behavior in 2004 found no connection between epileptic seizures and the full moon, even though some patients believe their seizures to be trigged by the full moon.  The researchers noted that epileptic seizures were once blamed on witchcraft and possession by demons, contributing to a longstanding human propensity to find mythical rather than medical explanations.
Psychiatric Visits: A 2005 study by Mayo Clinic researchers, reported in the journal Psychiatric Services, looked at how many patients checked into a psychiatric emergency department between 6 p.m. and 6 a.m. over several years.  They found no statistical difference in the number of visits on the three nights surrounding full moons vs. other nights.
Emergency Room Visits: Researchers examined 150,999 records of emergency room visits to a suburban hospital.  Their study, reported in American Journal of Emergency Medicine in 1996, found no difference at full moon vs. other nights.
Surgery Outcomes: Do doctors and nurses mess up more during the full moon?  Not according to a study in the October 2009 issue of the journal Anesthesiology.  In fact, researchers found the risks are the same no matter what day of the week or time of the month you schedule your coronary artery bypass graft surgery.

But not all studies dismiss the lunar influence:

Pet Injuries:  In studying 11,940 cases at the Colorado State University Veterinary Medical Center, researchers found the risk of emergency room visits to be 23 percent higher for cats and 28 percent higher for dogs on days surrounding full moons.  It could be people tend to take pets out more during the full moon, raising the odds of an injury, or perhaps something else is at work---the study did not determine a cause.
Menstruation:  This is very controversial and one of those topics on which you will find much speculation (some of it firm and convincing-sounding) and little evidence.  The idea is that the moon is full every month and women menstruate monthly.  Women's menstrual cycles actually vary in length and timing---in some cases greatly---with the average being about every 28 days, while the lunar cycle is quite set at 29.5 days.  Still, there is one study (of just 312 women), by Winnifred B. Cutler in 1980, published in the American Journal of Obstetrics & Gynecology, that claims a connection. Cutler found 40 percent of participants had the onset of menstruation within two weeks of the full moon (which means 60 percent did not).  If anyone can tell me how this oft-cited study proves anything.  However, in the 30 decades since this study appeared, nobody seems to have produced a study supporting Cutler's claim.
Animals Gone Wild:  A pair of conflicting studies in the British Medical Journal in 2001 leaves room for further research.  In one of the studies, animal bites were found to have sent twice as many British people to the emergency room during full moons compared with other days.  But in the other study, in Australia, dogs were found to bite people with similar frequency on any night.
SLEEP DEPRIVATION: In the Journal of Affective Disorders in 1999, researchers suggested that before modern lighting, "the moon was a significant source of nocturnal illumination that affected [the] sleep-wake cycle, tending to cause sleep deprivation around the time of full moon."  They speculated that "this partial sleep deprivation would have been sufficient to induce mania/hypomania in susceptible bipolar patients and seizures in patients with seizure disorders."  Unfortunately, these often-cited suggestions have never been tested or verified with any numbers or rigorous study of any kind.

Why do these myths persist?

If one presumes that modern lighting and mini-blinds have pretty much eliminated the one plausible source of human-related moon madness, why do so many myths persist?  Several researchers point out one likely answer:  It is a “confirmatory bias” in operation.  A confirmatory bias is operating when we tend to believe evidence that backs up our beliefs and reject evidence when it does not.  We do this all the time.  We do this when we have heard of the moon’s effect and then see evidence that looks like it could support that belief.  A confirmatory bias often puts a brake on our more sceptical thinking.  When strange things happen during a full moon, people notice the "coincidental" big bright orb in the sky and wonder.  When strange things happen during the rest of the month, well, they are just considered strange, and people do not connect them to the moon.  "If police and doctors are expecting that full moon nights will be more hectic, they may interpret an ordinary night's traumas and crises as more extreme than usual," explains Benjamin Radford, the columnist for the Bad Science website.  Radford adds, "Our expectations influence our perceptions, and we look for evidence that confirms our beliefs."  Putting all of this aside, perhaps the biggest logical nail in the coffin of the moon madness myths is this:  The highest tides occur not just at full moon but also at the new moon, when the moon is between Earth and the sun (and we cannot see the moon) and our planet feels the combined gravitational effect of these two objects.  Yet nobody ever claims any unusual happenings related to the new moon.  Interestingly, there is more beach pollution at the full and the new moon.  Yet somehow the full moon is a factor in odd occurrences, and the new moon is not.
No doubt, despite all of the contrary evidence, most of those people believing in the Lunar effect will not be swayed.  There are no werewolves and vampires either---except in the imagination.

*Based on the brief prepared from The Odd Body and various Internet prepared by Laura Speranza, producer for “Today”, Channel 9 T.V., Sydney, 14 December 2010.     
Frank Partnoy (Author)

 

News Archives: 2009 November 2009: Kindness Guerillas - Join the Fight! October 2009: Altruism Can Rule the Day September 2009: Our Lost Idyllic Childhood? August 2009: The Unknown Trauma of Child Abduction July 2009: Gekkomania Alive and Well June 2009: Why do we dance? May 2009: Exposing Sun Risks April 2009: Building Self-Esteem in Hard Times March 2009: Death by Anesthesia - Malignant Hyperthermia February: Why do we have no heroes today? January: Stress on young doctors 2008 December: Syllogomania September: How body language can work for you August: The blues busters July: 'Mother-to-be' fantasies are pregnant with meaning June: How kids cope with tragedies May: Things that Mums say: are they true? April: Future Items March: More body miscellany February: Where there's smoke... January: Is the Yeti now extinct? 2007 December: Odd Body Miscellany November: Teenage risk-taking behaviour October: Peyronie's Disease September: The Othello syndrome August: The new wrap on swaddling July: Where did the belief in guardian angels come from? June: What is real success? May: Is a time machine possible? April: What to say to someone who's dying March: More odds and ends behaviour February: Tiny machines will change us forever January: Do you have to be manic depressive to be creative? 2006 December: Sick Sperm November: Odd Statistics 1 August: Is it more natural for children to be cruel or kind? July: Satanic Cults Won't Go Away April: Something to Panic About March: Step This Way for an Argument February: Who's Afraid of Intimacy? January: Endangered Speciesism?