Final answer:
The word 'lunatic' is derived from the Latin word for moon, 'luna', due to the historical belief that the moon affected mental health, a belief debunked by modern research showing no correlation between Moon phases and human behavior.
Step-by-step explanation:
The term 'lunatic' has its roots in the Latin word 'luna', which means moon, and historically, it was believed that the moon could affect mental illness. This belief stemmed from the observation of increased erratic behavior during the time of the full moon, a phenomenon that gave rise to the term 'lunacy'.
However, modern studies and statistical analyses reject this notion. Investigations involving thousands of records from hospital emergency rooms and police files have shown no correlation between human behavior and the phases of the moon.
Rates of incidents such as homicides are consistent regardless of whether it's a new moon, crescent moon, or a full moon. The prevailing theory now suggests that rather than causing an increase in erratic or 'crazy' behavior, a bright full moon simply makes such incidents more noticeable or memorable.