A: Doctors classify chronic nail biting as a type of obsessive-compulsive disorder since the person has difficulty stopping. People often want to stop and make multiple attempts to quit without success. People with onychophagia cannot stop the behavior on their own, so it's not effective to tell a loved one to stop.
The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, categorizes chronic nail biting as other specified obsessive-compulsive disorder (OCD), classified in the same group as compulsive lip biting, nose picking, and hair pulling (American Psychiatric Association, 2013).
Nail-biting is frequently associated with anxiety, because the act of chewing on nails reportedly relieves stress, tension, or boredom. People who habitually bite their nails often report that they do so when they feel nervous, bored, lonely, or even hungry.
While most people assume nail biting has to do with nerves or anxiety, one study is linking this bad habit to a surprising personality trait. According to a study published in the March 2015 issue of Journal of Behavior Therapy and Experimental Psychiatry, nail biters are more likely to be perfectionists.
Many people bite their nails at some point, especially as children. It's a type of body-focused repetitive behavior that goes by the clinical name of onychophagia.
There can also be physical manifestations of the anxiety caused by ADHD such as headache, nausea, nail-biting or cuticle-picking.
For most people, nail biting is automatic: You do it without thinking about it. While it can occur without any underlying psychiatric conditions, it's also associated with attention deficit hyperactivity disorder (ADHD), separation anxiety, tic disorder, and other mental health problems.
Additionally, if you swallow the nails, they can do damage to the epithelial lining of your esophagus and stomach. They will not digest, so if they're sharp, they will make their way through your entire body potentially scratching up your digestive tract.
In fact, you may have heard how it takes 21 days to break a habit. This figure was popularized by a 1960s book called “The New Psycho Cybernetics” by Maxwell Maltz.
Sometimes, nail biting can be a sign of emotional or mental stress. It tends to show up in people who are nervous, anxious or feeling down. It's a way to cope with these feelings. You may also find yourself doing it when you're bored, hungry or feeling insecure.
But they do know that it's a habit for a lot of us: about 20 to 30 percent of the population are nail biters, including up to 45 percent of teenagers.
A: The behavior is typically automatic — people don't realize they're doing it. Chronic nail biting often has a self-soothing quality (it provides a sense of calm), so people may use it as a coping mechanism. Sometimes, a hangnail or nail imperfection could spur someone to excessively groom the nail.
Regularly biting your nails can cause your teeth to shift out of place, which can require correctional braces or a retainer. Nail biting could also cause your teeth to break or could damage your tooth enamel. The germs could also potentially infect, or cause irritation, to your gums.
Nail biters are more often male than female after age 10 (10% fewer bite their nails than boys), and individuals with a higher rate of intelligence tend to bite their nails more than those of less intelligence.
Once you've managed to stop biting your nails, one of the questions often asked is whether bitten nails can grow back to normal. The bad news is that although fairly uncommon, nail biting can lead to permanently damaged nails. You can cause permanent damage to your nails by biting them over a long period of time.
Nail biting can also transfer pinworms or bacteria buried under the surface of the nail to your mouth. When bitten-off nails are swallowed, stomach problems can develop.
"From chronic nail biting, you can damage the nail matrix (the tissue under the actual nail) and can have permanent nail deformities like ridges," explains Dr. Jaliman.
When you bite your nails, those bacteria end up in your mouth and gut, where they can cause gastro-intestinal infections that lead to diarrhea and abdominal pain.
To some degree, we all exhibit stimming behaviors. Nail biting, twirling your hair, drumming your fingers on the table, or cracking your knuckles are all forms of stimming. For a child with autism, stimming might involve motor tics like rocking back and forth, licking lips, flapping hands, or repetitive blinking.
They're nervous habits, or tics – such as biting your nails, twirling your hair, chewing on pens or pencils, or touching your face often – and they could be bad for your health.
Some of the reasons children bite their nails includes stress or anxiety, they are bored, they've seen other children do it and copy their behaviors, or their nails are not kept trimmed and they do it as a form of self-trimming. Most children that bite their nails have no problems.
They report that touching, rubbing or biting skin, nails, and hair prompts a relaxing, trance-like state, which distracts from negative emotions. When bored, body-focused repetitive behaviours can help people feel like they're doing something active, especially those with perfectionistic personality traits.
Fingernails grow about 3.5 millimeters each month
And toenails grow about 1.5 millimeters per month. Those are the averages for healthy adults. Whether you're getting proper nutrition and how well you take care of your nails can affect the growth rate.