The full moon triggers strange behaviour, crime, and hospital chaos.

Belief in 'lunar lunacy' is ancient and persistent: nurses, police, and teachers often swear that full moons bring more emergencies, crime, and disruption. The word 'lunatic' itself encodes the idea.

Rotton & Kelly (1985) meta-analysed 37 studies covering homicides, psychiatric admissions, crisis calls, and more, and found no meaningful correlation between lunar phase and human behaviour; the moon accounted for essentially none of the variation. Later reviews of births, emergency-room visits, and surgery outcomes reached the same conclusion. The persistence of the belief is a lesson in confirmation bias: memorable chaotic nights get attributed to a visible full moon, while ordinary nights and quiet full moons are forgotten. The claim is refuted.