Onychophagia

Onychophagia is a form of obsessive compulsive disorder where a person compulsively bites their nails. Sufferers can feel the pain they inflict on themselves but the feelings of gratification and stress relief prevent them from stopping. The severity and extent of damage to the skin is variable. Stress and anxiety can trigger the nail biting. The condition is most common in children with nearly half of teenagers biting their nails.