"Lunacy" - an adjective describing the effects of the full moon
on human behaviour, including an increase in pathology, crime
rates, violence, accidents and other psychiatrical
disturbances.
From :
http://www.innerself.com/Astrology/full_moon.htm
At the University of Miami, psychologist Arnold Lieber and his
colleagues decided to test the old belief of full-moon lunacy
which most scientists had written off as an old wives tale. The
researchers collected data on homicide in Dade County (Miami) over
a period of 15 years 1,887 murders, to be exact. When they
matched the incidence of homicide with the phases of the moon, they
found, much to their surprise, that the two rose and fell together,
almost infallibly, for the entire 15 years! As the full or the new
moon approached, the murder rate rose sharply; it distinctly
declined during the first and last quarters of the moon.
To find out whether this was just a statistical fluke, the
researchers repeated the experiment using murder data from Cuyahoga
County in Ohio (Cleveland). Again, the statistics showed that more
murders do indeed occur at the full and new moons.
Dr. Lieber and his colleagues shouldnt have been so surprised. An
earlier report by the American Institute of Medical Climatology to
the Philadelphia Police Department entitled The Effect of the Full
Moon on Human Behavior found similar results. That report showed
that the full moon marks a monthly peak in various kinds of
psychotically oriented crimes such as murder, arson, dangerous
driving, and kleptomania. People do seem to get a little bit
crazier about that time of the month.
Thats 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 isnt 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.
http://www.innerself.com/Astrology/full_moon.htm
For a deeper, more spiritual understanding of how the full moon
affects human consciousness, see Hilarion's explanation *here*.