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Habit disorders: How to prevent and treat nail biting

Nail biting is a very common habit that mostly affects kids but it can be present in adults and older people too. about it is manifested by biting one's fingernails or toenails during periods of nervousness, stress or boredom.

It can be a sign of mental or emotional disorder but is commonly seen in intellectuals. The medical term for nail biting is chronic onychophagia. It belongs to the group of disorders called Stereotypic movement disorders. Often starting in childhood, nail biting can persist in some adults and become an irritating and unsightly nuisance. Some nail biters experience the habit with such severity that their nails are constantly bitten down to the maximum and bleeding, causing pain and often embarrassment.


Several studies have shown that approximately 28% to 33% of children ages 7-10 are biting their nails, as well as the 44% of adolescents, 19% to 29% of young adults and 5% of older adults. It is more common in boys. Stereotypic movements are common even in infants and toddlers. Some estimates suggest that 15–20 percent of children under age three exhibit some kind of rhythmic, repetitive movements.

What is stereotypic movement disorder?

Stereotypic movements are described as a special psychiatric symptom, since they have symptoms of both psychotic and neurological disorders. They may also arise from unexplained causes.

These movements may include:

•    head banging
•    nail biting
•    playing with hair
•    thumb sucking
•    hand flapping
•    nose picking
•    whirling
•    body rocking
•    picking at the body
•    self-biting
•    object biting
•    self-hitting
•    compulsive scratching
•    eye gouging
•    teeth grinding (bruxism)
•    breath holding
•    stereotyped sound production

The exact definition is that these disorders include movements that cause physical harm or severely interfere with normal activities. Although, many think that it happens only to kids, this isn't true at all. Stereotypic movements occur in people of any age, including the very young, but they are most prevalent in adolescence.

People may experience one particular stereotyped movement or even several of them. The exact mechanisms and triggers are still unknown, but they seem to increase with boredom, tension, or frustration, and it appears that the movements are self-stimulatory and sometimes pleasurable.


Similar to stereotypic movements, a habit is a learned behavior that a person repeats so often that he or she begins to do it without even thinking about it. Certain habits can be helpful but some may seem to serve no particular purpose.

•    Helpful habits - brushing teeth before going to bed or buckling your seatbelt when getting into a car.
•    Habits with no purpose - hair twirling, thumb sucking, nail biting… etc.

Some habits are annoying, and some can cause distress or become the focus of teasing. Still others may have harmful effects. For example, thumb sucking, which can go on for years, can cause dental problems.

Is there a thing called ’’Physiological habit’’ ?
Some habit-like behavior is normal for a developing child. For example, approximately one half of all 2-year-old children engage in thumb sucking. However, if this behavior persists through childhood, the likelihood of it becoming a substantial problem may increase with age.

Possible causes of nail biting

Like any other stereotypic movement, nail biting can be caused by:

sensory deprivation (blindness or deafness)
drug use (cocaine, amphetamines)
brain disease (seizures, infection)
major psychiatric disorders (anxiety disorder, obsessive-compulsive disorder, autism)
mental retardation

Nail biting is, according to Freudian theory, a symptom of oral fixation.

It is very important to know that, although many situations can give rise to stereotypic movements, the root cause of stereotypic movement disorder is unknown.

Different theories propose that the causes are:


Although there are many theories about this disorder, no hard evidence clearly supports either line of reasoning or specific cause.

Symptoms of nail biting

The fact is that most childhood habits are benign and have no specific observable physical signs. However, when physical signs are present, they are typically non-pathologic and often previously unnoticed. It is proven that nail biting can be associated with the next symptoms:

extremely short fingernails
oral herpes
herpetic whitlow
damaged dentition
apical root resorption
fractures to the incisors

Nail biting can worsen some existing conditions of the nail bed, such as:

Infection of the skin around the nail (paronychia)

Warts around the nail bed

Negative side-effects of nail biting

Biting the nails can result in the transportation of microorganisms that are hidden under the surface of the nail into the mouth. This could lead to some very serious infections of the gums and lips. In fact, over 100 bacterial skin infections in 2000 were traced to footbaths in nail salons. It is proven that many pathogens have the ability to live and multiply inside of a nail, and still cause no significant symptoms. Nail biting also has the negative side effect of restraining the use of the hands. Although, they are afraid to admit it,  compulsive nail-biters can be restricted in their ability to work because their hand is in their mouth. These jobs include writing, typing, drawing; driving and other. It can cause not only damage to the nails but to the teeth also. The substantia adamantinea of the front teeth suffers most damage and it leads to  promoting caries in these areas.

Treatment of nail biting

The most common habits in children that require treatment can be significantly improved with behavioral interventions, without the use of medications. Sometimes however, in addition to behavioral treatments, medications may be required to attain optimal treatment outcomes.


Some of the nasty habits such as nail biting have been shown to respond well to certain types of medication. The medications used to treat the problem include the newest, most potent anti-depressants.

These medications include:


Anti-psychotics medications that are also being used are:


Behavioral Therapy

Beside the fact that most experts believe that behavioral therapy cannot be that much helpful, some patients have found behavioral therapy to be beneficial on its own or as a complement to medication.

The first part of nail biting therapy consists of :

Habit Reversal Training (HRT)

It is a four-step process which teaches how to get aware of your habbits, how to relax, how to breathe and focus yourself, and to perform a competing and opposing muscle response. It teaches you to replace the nail biting habit with a more constructive habit if possible.

Stimulus control (SC)

SC is a behavioral treatment that seeks to help sufferers identify, and then eliminate, avoid, or change the particular activities, environmental factors, mood states, or circumstances that have become associated with, and that trigger picking or pulling. The goal of this part of the therapy is to consciously control these triggers that lead to the undesirable behaviors, and to create new learned connections between the urges and new non-destructive behaviors.


Hypnotherapy can help you to form positive new alternatives to nail biting and  help you cope with anxious situations and stress triggers in a constructive way.

A hypnotherapist can also work with your unconscious mind to stop this unconscious habit.

Other Treatments

Various forms of aversion therapy exist to help people stop biting their nails. These include:

Coating the nails with a bad-tasting substance (sometimes in the form of a special nail polish)

Wearing a rubber band on their wrist

Having friends and family members snap it when they see nail biting.

Keeping a record of when one bites may also be helpful in finding the root of the problem.
Orthodontic treatment - Some nail biters who undergo this kind of treatment find that wearing a bite plate makes it impossible for them to bite their nails with their teeth.

Unfortunately some compulsive nail-biters, find the effectiveness of all of these remedies to be poor. Like other nervous habits, nail biting is sometimes a symptom of an emotional problem. In these cases, resolving the underlying problem can help to lessen or eliminate the nail-biting habit.
Tips for parents

Keep the kid’s hands occupied.

Cut the fingernails short so there's nothing to tempt the kid to bite.

Wait and hope

Check it out with some health specialist

Nail biting is a common habit. Although unsanitary, it typically causes no long-term nail problems. The fact is that most of the childhood habits that do not involve self-injury are benign and disappear without any special intervention. When a habit persists and interferes with daily functioning, intervention is warranted.

The prognosis for reducing and eliminating habit disorders is typically good.

Treatment research shows that behavioral intervention can reduce the habit behavior by 90%.

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