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Lunatic -

For centuries, physicians and philosophers blamed behavioral changes on the Full Moon. As a matter of fact, the word "lunatic" stems from the idea that changes in mental state were related to lunar cycles.

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An old belief -

The link between the Moon and a change of mental state has even been supported in historic legal treatises. For example, British jurist William Blackstone argued that people gained and lost their ability to reason according to the Moon's shifting phases.

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The lunar effect -

The "lunar effect" is based on the belief that health and behavior are altered during specific stages of the lunar cycle. Some even claim that it can affect everything from reproductive health to sleep quality.

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A natural phenomenon, but not for humans -

The belief that lunar phases also influence humans mostly stems from the Moon's influence on natural phenomena, like the tides. But these persistent beliefs are mostly incorrect.

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Sources of superstition -

The idea that the Moon impacts certain aspects of physical and mental health can be traced back to ancient Greece and Rome and classical thinkers like Aristotle and Gaius Lucilius.

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Aristotle and the Moon -

The cyclical seizures of epilepsy were also attributed to the Moon’s influence. Greek philosopher Aristotle believed that during the Full Moon children were more prone to epileptic attacks.

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The ancient power of the Moon -

The ancient Greek physician Hippocrates proposed that "one who is seized with terror, fright, and madness during the night is being visited by the Goddess of the Moon."

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Biological tides -

During the '70s, psychiatrist Arnold Lieber theorized that the Moon influenced the body’s "biological tides."

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Lieber's theory -

Lieber suggested that because the human body is about 70% water, humans experience tidal shifts caused by the Moon's phases. He argued that under a Full Moon, the occurrence of murder, suicide, aggravated assault, psychiatric emergencies, and fatal auto accidents increased dramatically.

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Theory dismissed -

While Lieber's theory seems reasonable at first, it was quickly dismissed by experts. One study argued that Earth's gravitational pull is 5,012 times stronger than the Moon's, whose pull is no more than the weight of a flea. So while the Moon might regulate the tides of large, open bodies of water, it won't affect a glass of water or a tub—let alone the water that makes up the human body.

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The Moon and menstrual cycles -

The Moon takes about a month to orbit the Earth. Since many menstrual cycles are about the same length, people have made a connection between the two. But studies have shown that they're actually not synchronized.

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Births during Full Moons -

Pregnant women are also rumored to be more likely to give birth on a Full Moon, but any scientific evidence for this is inconsistent.

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Full Moon and your sleep -

Studies have found that the Moon might affect your sleep. One 2021 study in particular discovered that people fell asleep later and slept less on the nights before the Full Moon.

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Possible Full Moon effects -

Other studies suggest that the Full Moon might also be associated with increased rapid eye movement (REM) latency.

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Sleep latency -

Sleep latency is the period between when you first fall asleep and when you enter the first stage of REM sleep. Increased latency means it takes a longer time to get to REM sleep. Sleep apnea, alcohol, and certain medications can also cause REM sleep latency.

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Less deep sleep -

Another study, this one from 2013 and measuring brain activity, suggested that the amount of deep sleep experienced dropped by 30% during a Full Moon. 

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Further research is needed -

However, further research is needed. as studies haven't monitored individual patients’ sleep over an entire lunar month, or many months. The best thing to do would be to record the same individual continuously over different phases.

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The Full Moon may affect sleep differently in men and women -

A 2015 study found that many women slept less and had less REM sleep when the Full Moon phase was near. Men in the study had more REM sleep close to a Full Moon.

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The Full Moon and children -

In 2016, a group of researchers examined the sleep cycles of 6,000 children in 12 countries. The findings revealed that sleep duration was about 1% shorter during a Full Moon compared with a New Moon. However, they didn’t find any association between this change in sleep and differences in behavior during that period.

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Mood and mental health -

The human body has adapted to eons of exposure to daylight and darkness. This has developed the circadian rhythms that affect our physical and mental health.

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How it's connected -

But the widespread use of electric light means many of our circadian rhythms are adapting to new light and dark patterns. When circadian rhythms are disrupted, it can increase mental health disorders, such as anxiety and depression.

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The Full Moon and the circadian rhythm -

So does the Full Moon still have the power to disrupt your circadian rhythm? As it brightens the night sky, you would assume yes and that it's associated with changes in mood and mental health.

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Not really the case -

However, the prevailing scientific evidence says no. A 2017 study, which analyzed emergency room records, found that the number of people who visited the ER because of a psychiatric condition was roughly equal during all Moon phases.

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Those with bipolar disorder may be affected -

However, there's one exception. Researchers have found that those with bipolar disorder may be affected by changes in the lunar cycle.

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The study -

This 2018 study looked at 17 people whose bipolar disorder tended to switch rapidly from depression to mania.

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The findings -

The study showed that the circadian pacemaker, a small group of nerves, in these individuals became synchronized with lunar patterns. This resulted in changes in their sleep, which then triggered a shift from depression symptoms to mania symptoms.

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Potential treatments -

In a 2019 case study of a woman with bipolar disorder, researchers suggested that this could be treated by changing some medications, especially thyroid medications and antidepressants. Using light therapy was also suggested.

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Full Moon and violence -

For centuries, people have persisted in believing that there are more assaults, violence, and suicides during Full Moon periods. However, many researchers have found that a Full Moon doesn’t cause an increase in these behaviors.

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Takeaway -

Studies are still being conducted on how the Moon influences various physiological and psychological systems. But for now, the Moon's effect on your body is widely accepted as less powerful than once believed.

Sources: (BBC) (Healthline) (Cleveland Clinic) 

See also: The biggest women’s health myths

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