The Moon Is Still Messing With Us

It must have been weird before electricity was widespread, and around 6PM the whole world went dark, save a mysterious white circle of light glowing from the sky. It’s no wonder humans started pointing fingers at the moon to justify our strange nocturnal behavior. There was literally nothing else around to point at.

Centuries later, we can’t shake the notion that we have a cosmic connection to Earth's neighbor, and scientists have conducted study after study to try and prove, or disprove, the intuitive belief that the lunar month influences our body and mood—especially during the full moon.

You know the myths: that the full moon makes people act a little crazy (the word lunatic originates from the Latin word for “moon” and its old English counterpart "monsoon," which literally translates to "moon sick”). Supposedly it causes more hospital visits, epileptic seizures, restless sleep, psychological meltdowns, and criminal acts. Yet for every study that backs up those beliefs, there’s one that busts the myth, leaving us no closer to having any real proof how–or even if–we're biologically tied to the moon.

This week we can add another study to the "yea" column. Biologists at the University of Basel in Switzerland found evidence that people sleep more poorly when the moon is full. Lead researcher Christian Cajochen studied the sleep patterns of 33 volunteers over three years, for reasons entirely unrelated to the moon. Then one day while chatting over a beer at a pub, he realized he could take a second look at the data and see if there was any correlation in people's sleep patterns and the phases of the moon at the time.

Sure enough, there was. The majority of participants in the study, which was published yesterday in the journal Current Biology, slept about 20 minutes less on and around the full moon, and had lower melatonin levels. They took longer to fall asleep and reported a more restless sleep on those nights—even the people who were sleeping in windowless rooms.

If you're already skeptical, you’ll be interested to learn that a similar sleep study, this one from 2006, that was also not originally intended to look at a potential lunar influence on sleep, found almost the exact same thing. The subjects slept about 20 minutes less during the full moon, and reported being more tired the next morning.

The findings suggest we're biologically influenced by the monthly lunar cycle, or lunar rhythm, the same way we're influenced by the sun’s rhythm throughout the day, Cajochen wrote. “Lunar rhythms are not as evident as circadian rhythms and are thus not easy to document. But they exist. Their role is mysterious."

Hundreds of years ago it would be harder to sleep during a full moon because the moonlight is so much brighter, so maybe that psychological pattern still has sway over our body, even though modern advances like electricity and curtains have made it irrelevant. Logical enough. "It would be interesting to look at this in people still living outside without artificial light, but light from fireplaces," Cajochen told LiveScience.

If the lunar cycle’s influence over us has faded since the advent of artificial lighting, that could explain why scientists find more evidence of the moon affecting the behavior of other animals and plant species.

There's a big uptick of cat and dog emergency room visits on the days around the full moon, a study of nearly 12,000 pet-injury cases at the Colorado State University Veterinary Medical Center found. Another study in the journal Behavioral Processes found that wolves were less active during a brighter moon, because prey are less likely to venture out and the predators follow suit. And then there’s the massive coral sex phenomenon, that fills the sea with coral sperm and eggs in the days following the full moon.

Sleep and sex are intuitive enough to blame on the glowing ball in the night sky. But what about the persistent myth of moon-powered madness? Well, some scientists speculate that throughout history, disrupted sleep could have triggered people with mood disorders to experience extreme behavior, like bringing about mania in people with bipolar disorder, or seizures in people with epilepsy.

That's just one theory. Others have speculated that the moon's gravitational pull, master of the ocean tides, can also affect the flow of fluid to the human brain, altering mood. Yet again, the science to back up the speculation is shoddy at best, and the majority of studies can’t find any scientific claim to these theories.

To name a few, a recent buzz-kill study out of Quebec debunked the myth of any lunar influence on mood, as did another meta-study, "Much Ado About the Moon," back in 1985, which additionally suggested that past studies that did find a correlation between the lunar cycle and mental health were fundamentally flawed. A 2010 study published in the Journal of Criminal Justice also found no link between a full moon and crime. Even Cajochen himself isn't convinced yet.

So why has the myth persisted so long? Maybe we just really want it to be true, naysayers suggest. Biased expectations can make us seek out evidence to confirm what we already believe is true. Maybe it's all in our heads, or maybe we just haven't discovered the secret yet. Maybe the research is flawed and methodology underdeveloped, or maybe our imaginations have run wild. It's a mystery we're still waiting for science to solve.