Psychology of Nail Biting

There are a variety of reasons for nail biting, depending on the person who is doing it. Also known as onychophagia, this habit can be simply that, a habit, or it can be caused by an underlying disorder like anxiety. In general, the different theories lead back to behavior modification as a solution to ending the biting.

Theories

• One theory is that onychophagia is caused by an obsessive-compulsive personality. People who bite their nails may fit the diagnostic criteria of obsessive-compulsive disorder or body dysmorphic disorder, according to psychologist M. Williams. Other theories say that nail biting is a form of self-soothing related to increased anxiety. On the flip side, some onychophagia sufferers may bite because they're bored and are looking for some kind of stimulation. In many cases, nail biting continues into adulthood as a remnant from the adolescent years as it has then become an unconscious habit.

Prevalence

• Although exact numbers are hard to pinpoint, it is estimated that about 30 percent of children 7 to 10 years of age bite their nails, 44 percent of adolescents do so, about 20 percent of young adults bite and 5 percent of older adults continue the habit. It is also thought that more males suffer from onychophagia than women.

Risks

• The main risks of nail biting are those related to infection. When a person bites their nails down to the nail bed, bleeding can occur, a signal of an open wound. The potential for infection arises because the hands are always touching things, but also because continuous biting can introduce germs from the mouth into the wound. Other risks are not physical in nature, but rather social and cognitive; people who bite their nails may be embarrassed by their hands or feel ashamed of themselves, leading to low self-esteem.

Treatment

• Although medications like antidepressants may help in treating people who wish to stop biting their nails, behavior modification is the more effective way of getting the habit under control. These treatments focus on becoming aware of the action (self-monitoring), figuring out what may be triggering the response, altering thought patterns that lead to the behavior and changing the behavior itself. Any type of habit reversal therapy may be effective in treating onychophagia if the person really desires to stop and has the motivation to stick with a program that can be quite lengthy (up to a year in many cases).

Related Disorders

• Many people who bite their nails may also bite their cuticles or the area around the nails as well, and this is defined at dermatophagia, or biting of the skin. Trichotillomania, or hair pulling, and trichotillophagia, hair eating, are also thought to be related to onychophagia.