It makes our fingers look ugly. It's dirty. It could hurt a lot. But many people just can't stop doing it: biting their nails (咬指甲).
Up to 45 percent of teenagers in the UK bite their nails, according to the BBC. Some people bite their nails not because they're too long, but because they are driving, feeling stressed out, or just have nothing else to do.
In 2013, the American Psychiatric Association identified nail biting as a symptom (症状) of obsessive-compulsive disorder (OCD, 强迫症). People with this disorder may wash their hands more often than usual or have to line up their shoes in a certain way.
Although nail biting has some things in common with other symptoms of OCD, it is different from them in at least one way.
"In OCD, the behavior is really unwanted," said psychiatrist Carol Mathews. People with OCD don't want to wash their hands over and over again. There is no fun in it. They just fear that if they aren't busy doing something, something bad might happen to them.
But nail biters enjoy this activity. "It's rewarding. When you get the right nail, it feels good," said Mathews. Therefore, some people argue that most nail biters do not have any kind of serious mental illness.
However, it's still a bad habit. So what can we do to stop it? Since most people bite nails as a way of relieving (缓解) stress, finding another way to relieve that stress could be useful, suggested Rochelle Torgerson, a doctor at the Mayo Clinic in the US. For example, some people might play with a pen instead.
Nail biters feel the urge (冲动) to bite if they find a small part of the nail that is imperfect, Mathews said. So always keep your nails in good shape.
