Other mistake: When the two Americans are walking on the moors, their shadows are always in front of them, despite them having changed direction numerous times. Additionally, with the moon always being behind them, how are their faces being lit?
Other mistake: When David changes into a werewolf for the first time you can see his huge feet vibrate when he moves his legs in agony: they are made from rubber.
Answer: He was referring to the local residents that lived in the area who, unknown to the doctor, knew about and were terrorized by the werewolf that roamed the countryside during a full moon. The doctor thought they suffered from some type of mass mental illness.
raywest ★