The gravitational force of the moon is strong enough to cause the ocean to rise (causing high tide) and therefore it is possibly changing the gravitational effect on our glands and organs which can affect our moods. During the night, the full moon counteracts the gravitational pull on us from the Earth, and during the day its complete absence overhead would allow the Earth's gravitation to have an unobstructed affect on us. This gravitational difference between mid-day and midnight is the greatest during the days of the full moon (and new moon when the moon is overhead during midday and absent during the night). It is one explanation for a persons more erratic behaviour during this time (and also during the new moon for some people).
Some animals change in behavior also during the changes of the moon, much as humans, their moods/actions seem influenced as well as sexual behavior seem more prominent during different phases of the moon.
That’s something most police and hospital workers have known for a long time. Indeed, back in eighteenth-century England, a murderer could plead “lunacy” if the crime was committed during the full moon and get a lighter sentence as a result. Scientists, however, like to have a hard physical model to explain their discoveries, and so far there isn’t a fully accepted one. Dr. Lieber speculates that perhaps the human body, which, like the surface of the earth, is composed of almost 80 percent water, experiences some kind of “biological tides” that affect the emotions. When a person is already on psychologically shaky ground, such a biological tide can push him or her over the edge.