From the Springfield (Mo.) News-Leader:

So, if the effect is a myth (as most experts say it is), how did the full moon get associated with wild behaviors in the first place? After all, there’s a long history of blaming it for acting out — the term “lunatic” has its roots in the word “luna,” which is Latin for moon.

William Wedenoja, a professor of anthropology at Southwest Missouri State University, wonders whether the full moon had more of an immediate effect on people’s behavior in the past.

“Basically (without artificial lighting) it’s dark after the sun goes down, but if there’s a full moon, you can stay awake later into the evening,” Wedenoja said. That means, before artificial lighting, people could be more active on full-moon nights.

Also, Wedenoja said, a connection between full moons and out-of-the-ordinary events could be more a perception than a fact.

“We have the persistency to believe things even when there’s no foundation,” he said. “If you expect your patients to act odd on a full-moon night, they are always acting odd.”

On the other hand, there’s this exchange from Abbott and Costello Meet Frankenstein:
Larry Talbot: You don’t understand. Every night when the moon is full, I turn into a wolf.
Wilbur: You and twenty million other guys!

I am sure the Police and Hospitals would take exception to the “experts”

Heck…I take exception!

They certainly do in the story (the reporter did a pretty good job):

“It’s not supported by empirical evidence,” said Debbie Fugett, a labor and delivery nurse at CoxHealth. “But on the night when there’s a full moon, we’re just a little bit nervous of what to expect.”

“You get everything — just people doing crazy stuff: they imagine people, chase cows and see people in the woods.”