Nail biting is more than a bad habit. Doctors say it is one of the most common symptoms of stress or of an obsessive-compulsive disorder, especially for teenagers or younger children, and can lead to disfigurement and serious infection.
Now a Dutch businessman, Alain-Raymond van Abbe, is offering what he calls sure-fire cure.
Four weeks flat you can get rid of that habit for ever, he claims. He is relying on a tooth guard molded to fit either the upper or lower teeth. Barely visible, the 'preventer' makes it impossible to bite, but can be removed for eating.
Abbe, a former health industry and cosmetics promoter, estimates the world's pathological nail biters number 600 million or more. He saw that onychophagy (as the habit is called) was so widespread that he has opened a business devoted to a cure.
'After four weeks, the impulse disturbance is so frustrated that it is controlled. You don't have any problem any more,' he said.
Studies show around 45 percent of adolescents nibble their nails. That drops to about 20 percent as young adults learn to cope with their anxieties or become too embarrassed by their self-inflicted deformity.
In public, compulsive biters typically keep their hands out of sight as much as they can, buried in their pockets or behind their backs. They often feel depressed and shamed, and avoid social contacts. Van Abbe says his clients suffer so much from the stigma that none would volunteer to be interviewed or photographed.