Lunatic

That word (lunatic) comes from the word Luna, the Latin word for moon. Luna also means moon in Spanish. And lunatico means lunatic in Spanish.

Lunatics are people who are affected negatively by the moon's phases, specially the full moon.

The moon has a definite gravitational pull on bodies of water such as our oceans. It's the moon's gravitational pull that causes the low and high tides, just depending on where the moon is.

Water makes up to 60% of our bodies. So there's no doubt in my mind that the moon's gravitational pull has an effect on our bodies and emotions which often times surfaces as lunacy during a full moon.

Full moons also affect those shape-shifters known as werewolves.