Does living in a city make you psychotic?
Christian Bale in American Psycho

Gut Check is a periodic look at health claims made by studies, newsmakers, or conventional wisdom. We ask: Should you believe this? The claim: Living in a city makes people develop schizophrenia. Tell me more: The claim is not quite that stark, but it's close. For a study published last week, researchers interviewed 2,063 British twins…