Cleanliness is Next To Godliness
A strict religious upbringing may cause obsessive-compulsive disorder. This was discovered by Claudio Sica at the University of Parma in Italy who surveyed devout Catholics and found they were more likely to have symptoms of this disease than less religious people.
Patients with OCD become caught up in repetitive mental cycles. They have to have to wash the dishes thoroughly before putting them in the diswasher. They may be convinced that everything around them is filthy, and spend eight hours a day cleaning. They may obsessively wash their hands, like Lady MacBeth.