Are epileptic seizures more common during a full moon?

By: Alia Hoyt
Jakarta, Indonesia residents ride a truck through a flooded street after an unusual high tide in November 2007.
Adek Berry/AFP/Getty Images

As the Earth's lone natural ­satellite, the moon and the mystery surrounding it has long been credited with causing a host of seemingly mystical occurrences. Some of these happenings are scientifically based, including the moon phase's indisputable effect on the Earth's ocean tides. Others, however, seem to be inspired more by a combination of folklore and fear.

For example, the full moon has been associated with the appearance of werewolves, as well as increased levels of insanity and chaos in the form of crime and accidents. These superstitions date back so far in fact, that "luna," the root of insanity-inspired words such as "lunatic" and "lunacy" is Greek for "moon." The full moon is also often blamed for some less frightening phenomena, including increased birthrates, sleepwalking and even substantial casino payouts. The question that has puzzled epileptics for years, however, is whether or not epileptic seizures are more likely to occur during a full moon.


Long before the space race ever began, scientists and ordinary people alike theorized about the full moon's impact on the Earth. Their theories resulted in sometimes legitimately concerning, but often wildly unfounded beliefs. As so many scientifically unsubstantiated theories do, these ideas snowballed over time until they were considered factual, despite a decided lack of scientific evidence.

Multiple scientific studies have found that highly educated health care professionals, police officers and mental health workers subscribe to the notion that increased levels of trauma and crime occur during full moons [source: ABC News]. One widely held full-moon-related belief involves a disorder that at one time elicited much fear from the general population -- epilepsy.

Epileptic seizures are an involuntary and largely unpredictable side effect of epilepsy, a neurological condition often caused by brain tumors or malformations, head trauma, brain lesions and other unknown factors. Epilepsy, while still very frightening to those that suffer from it, used to be much more feared and misunderstood before modern science began to make headway into understanding its causes and treatments.

It's no wonder, given society's tendency to fear the unknown, that epileptic seizures used to be associated with black magic and demonic possession, rather than legitimate medical conditions. It seems natural that this fear would morph into an association with the full moon and its "power" over the human body, leading many to question whether or not more epileptic seizures happen during full moons. Is it possible that the moon, from its distant orbit nearly 250,000 miles (402,336 km) away can exert such influence over the human mind and body?


Putting Full Moon Theories to the Test

Pregnant women gather in a park in Oeiras, Portugal for an event to celebrate birth in July 2007. Some people believe that a full moon causes an increase in birthrates.
Rodrigo Cabrita/AFP/Getty Images

Although fear surrounding epileptic seizures had been around for centuries, the connection to the full moon's supposed strength was popularized in 1978 when a psychiatrist named Arnold Lieber published "Lunar Effects: Biological Tides and Human Emotions." In a nutshell, the book emphasized the moon's ability to utilize gravitational pull in a way that affects humans.

Some people bought into this idea because the moon's gravitational pull does impact the Earth's ocean tides. Lieber further detailed his "biological tides" theory, which noted that, since the human body is 80 percent water, it stands to reason that the moon can control it in the same way it controls the ocean's water. Unfortunately for Lieber, the majority of scientists now concur that the moon is far too distant to make an impact on teeny-tiny humans, even if we are made up mostly of water. Nevertheless, Lieber and others plugged away. He even published an updated version of his book as recently as 1996.


A few studies have claimed to show a connection between the full moon and various consequences, but they're often discredited due to problems with the scientific methodology used. In 1996, three scientists -- Ivan Kelly, James Rotton and Roger Culver -- released findings from their own review of more than 100 studies dealing with lunar effects. They found that the studies failed to present a significant correlation between the full moon and any of the behaviors it supposedly causes.

A team of University of South Florida researchers completed what they believe to be a definitive answer to the question of whether or not the full moon causes epileptic seizures. The team reviewed 770 seizure occurrences over a three-year period that took place in the epilepsy monitoring unit at Tampa General Hospital. The goal, of course, was to determine whether or not epileptic seizures occurred more often during full moons.

The study, which was published in the scholarly journal "Epilepsy and Behavior," revealed that the full moon period actually had the fewest epileptic seizures with only 94. The moon's last quarter boasted the most, with 152. These results led the scientists to conclude that there is no significant correlation between the full moon and increased incidence of epileptic seizures.

As far as the many full moon theories go, research has yet to validate any of them. Despite this fact, the theories persist among the masses of pregnant women who have gone past their due dates, epileptics who yearn for some way to predict their seizures. Kelly, Rotton and Culver believe there are several reasons that these beliefs continue to pervade modern society, despite a lack of solid evidence:

  • Media influence (presentation of the full moon and related myths in movies, television, books, etc.)
  • Folklore and tradition
  • Common misconceptions
  • Cognitive biases (the misconception has been repeated so many times by influential people that others take it as fact without questioning it)

It is doubtful that 100 percent of the population will ever accept the moon's limitations as fact. However, the vast majority of the scientific community does. Can believing in these myths hurt anyone? Probably not. In fact, it can be kind of fun placing pregnancy due date bets based on the lunar calendar. Just don't gamble your life savings away on it.


Lots More Information

Related HowStuffWorks Articles

More Great Links

  • Epilepsy Foundation
  • Francescani, Chris and Brittany Bacon. "Bad Moon Rising: The Myth of the Full Moon." ABC News Web Site. 21 March 2008.
  • "Full Moon Exerts No Pull On Frequency Of Epileptic Seizures." University Of South Florida Health Sciences Center. ScienceDaily. 26 May 2004. 11 May 2008.­ /releases/2004/05/040526065332.htm
  • "The Influence of the Full Moon on Seizure Frequency: Myth or Reality?" University of South Florida Health Sciences Center. 1 April 2004.
  • Kole, William J. "Full Moon Myths Debunked." Discovery Channel. Aug 2007
  • Meers, Nancy, Pediatric Nurse Practitioner with the Children's Epilepsy Center at Children's Healthcare of Atlanta at Scottish Rite. Personal interview conducted by Alia Hoyt. Apr. 4, 2008.
  • "Moon."
  • Pubmed_RVDocSum