Ha, its a myth people go crazy on a full moon. Was just discussing this.
A research team looked at 700 000 admissions to psych wards, police stations and hospitals and there was NO DIFFERENCE at all when there was a full moon or not.
It is simply confirmation bias- ie: something happens that you believe, and you go, there old mate is crazy its a full moon. Whereas if he went crazy and it wasn't a full moon we don't think anything of it