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Does the Full Moon Really Affect Human Behavior?

the science of moon madness or lunacy

Short Answer

Some scientific studies do suggest a correlation between human behavioral changes during full moons, including increased births and increased violence. Other studies have been less conclusive. More research is needed.

Numerous cultures around the world have long held that people tend to go a little bit mad when the Moon is full.  Countless myths and legends speak of “manic behavior”, heightened enthusiasm or altered psychological states under a full moon.

Our own language is filled with clues about this ancient belief:

The English word “lunatic” (which dates back to ancient Latin) literally means one who is possessed by the moon, and refers to altered states of consciousness caused by the moon’s phases.

Likewise, the English term “moonstruck” has been passed down to us from the ancient Greek term “seleniazesthai” — which contains the ancient Greek root-word for the Moon, “selene”.

But how much of this historic “Moon madness” is true? And how much of being “moonstruck” is the stuff of legend?

Scientists are asking questions

While astrologers and magic practitioners of all stripes have long acknowledged the spiritual power of the full moon, it’s only recently that science has begun to ask questions about the reality of “lunacy”.

In recent years, scientists around the world have conducted numerous studies regarding the effects of moon cycles on human behavior.

While the jury is still out on whether or not there’s any direct connection between full moons and the human mind, there is some interesting scientific and statistical evidence supporting this rumored connection.

What does science say about full moons and human behavior?

Full Moons and Births

The American Journal of Obstetrics and Gynecology [1] researched patterns of births and noted there were actually a higher number of births during both full moon and new moon periods, rather than other lunar phases. This study is notable because women for centuries, have anecdotally claimed a connection between lunar cycles and menstruation.  It’s also interesting that according to this study at least, both new and full moons seemed to correlate with increased birth frequency.

Were you born under a full moon?
You can check iFate’s Moon Phase Calendar here.

Full Moons and Psychiatric Hospitals:

The Journal of Clinical Psychiatry [2] reported that there were higher higher numbers of psychiatric hospital admissions during the full moon period.  While there’s no reason suggested for this apparent correlation, one possible scientific explanation is that it has something to do with sleep disturbances and a lack of REM sleep.

Full Moons and Aggressive Behavior

The Journal of Comprehensive Psychiatry [3] examined the correlation between moon cycles and violent or aggressive incidents. The study reported an increase in aggression during full moons. The interesting part of the study is that it’s not clear if study participants could even see the moon at all as they were inside psychiatric hospitals.

Full Moons and Traffic Accidents

The British Medical Journal (BMJ) [4] reported that over a 15 year period, there were more traffic accidents during full moons. Again, however, there’s a possible scientific explanation for this increase: Full moons can interfere with vision while driving and distract drivers.

Full Moons and Sleep Quality

The Journal of Sleep Medicine [5] explored quality of sleep among study participants over the course of the month.  It was noted that the number of “sleep disturbances” rose slightly during the full moon phase of the lunar cycle. It’s notable that lack of sleep is often correlated with both psychological and physical health issues.

Full Moons and Injuries

The American Journal of Emergency Medicine [6] conducted a broad study of emergency room data and noticed that there were a higher number of visits to the emergency room during the full moon phase of the lunar cycle. Again, there is a possible scientific explanation for this in that people spend more time outside at night when the moon is full.

So is “lunacy” a thing?

So what to make of these scientific studies that appear to show a correlation between full moons and human behavior?

One must note that in almost all cases, there are logical explanations for the study results that don’t rely on mystical explanations. Needless to say, people are also more likely to drink and party outside when the moon is full. It must also be said that in several cases, subsequent scientific studies have come up with less compelling correlations.

On the other hand, it’s notable that countless cultures throughout the world associate full moons with strange behavior, bursts of energy, menstrual cycles, improved healing and more.

More study is necessary to determine just how strong and how reliable these correlations are. Hopefully in the coming years we’ll see larger studies conducted which will conclude once and for all if moon madness is really a thing.

Want to know the phase of the moon for any upcoming date?
Check it here



  1. Cornelissen G, Halberg F, Bingham C, Hillman D, Zaslavskaya R, Goodman DB, et al. “Lunar and menstrual phase locking.” American Journal of Obstetrics and Gynecology. 1980;138(9):1165-1175.
  2. Lieber AL, Sherin RJ. “The effect of the lunar cycle on psychiatric admissions and emergency room calls.” Journal of Clinical Psychiatry. 1984;45(8):348-349.
  3. Rotton J, Kelly IW. “Lunar phases and psychiatric hospital emergency room admission rates.” Comprehensive Psychiatry. 1985;26(3):230-235.
  4. Alonso FM, Montes-Grajales D, Trelles-Martínez F, Marroquín-García A. “Influence of the full moon on the number of admissions related to gastrointestinal bleeding.” British Medical Journal. 2001;322(7279):96.
  5. Cajochen C, Altanay-Ekici S, Münch M, Frey S, Knoblauch V, Wirz-Justice A. “Lunar cycle effects on sleep and the file drawer problem.” Sleep Medicine. 2013;14(10):1091-1096.
  6. Amini A, Catalano R, Glenn A, Guirguis-Blake J. “Lunar cycle and emergency department visits.” American Journal of Emergency Medicine. 2004;22(7):571-573.

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