Negative side-effects
Biting the nails can result in the transportation of germs that are buried under the surface of the nail into the mouth. In fact, nail salons use tools that potentially affect a human in a similar way. "If are used on different people, these tools may spread nail fungi, staph bacteria or viruses," warns Rick Lopes, a spokesperson for the California Board of Barbering and Cosmetology. Thus, one can see that many pathogens have the ability to "live" inside of a nail, and because of this biting the nails can potentially cause health issues.
A compulsive nail biter could also be tempted to bite not only the nail, but also the surrounding skin and cuticle, possibly breaking skin. An broken skin is susceptible to opportunistic microbial and viral infections. These pathogens can be spread between the fingers and toes via the mouth. A normal, healthy (nail biting) person has a very low risk of suffering from infections.
Nail biting also has the negative side effect of restraining the use of the hands. A compulsive nailbiter can be restricted in their ability to work (i.e. writing, typing, drawing, playing stringed instruments, driving) because of the damage done to the nail or surrounding skin and/or anxiety in regards to the appearance of their nails.
A long-time habit of nailbiting may have detrimental effects on the substantia adamantinea of the front teeth, promoting caries in these areas.
Medication
Nail biting has 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 are also used to treat Trichotillomania and OCD and include clomipramine, fluoxetine, sertraline, paroxetine, fluvoxamine, citalopram, escitalopram, nefazodone and venlafaxine. Also, small amounts of the anti-psychotics used to treat schizophrenia such as risperidone, olazapine, quetiapine, ziprasidone, and aripiprazole can be used to augment anti-depressants. It is important to note that the use of anti-psychotics to treat nail biting does not necessarily indicate that the patient is suffering from psychosis.
Another option calls for the use of the B vitamin inositol. It reduces the urge to bite by enhancing the activity of serotonin in the brain. Serotonin may be implicated in OCD and related disorders.
Behavioral therapy
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), a four part process that seeks to "unlearn" the habit of nail biting and possibly replace it with a more constructive habit. In addition to HRT, Stimulus Control therapy is used to both identify and then eliminate the stimulus that frequently triggers biting urges..
The symptoms have been found to respond best to a combination of medication and therapy.
Other treatment
Various forms of aversion therapy exist to help people stop biting their nails. These include methods such as coating the nails with a bad-tasting substance (sometimes in the form of a special nail polish) or wearing a rubber band on their wrist and having friends and family members snap it (or tell the nailbiter to snap it) when they see nailbiting. Replacing the habit of biting nails by the habit of chewing gum works for some people. Some methods (including aforementioned aversion methods) can work by making the biter aware of their actions and finding other things to do. Keeping a record of when one bites may also be helpful in finding the root of the problem.
Some nail biters who undergo orthodontic treatment find that wearing a retainer or a bite plate makes it impossible for them to sever their nails with their teeth. This can have the unintentional side-effect of helping the individual to overcome their nail-biting habit.
Some nail-biters, however, find the effectiveness of all of these remedies to be poor. For them, it may take sheer determination to break the habit. Tactics they may find helpful include making a mental note to stop, promising oneself not to bite, and making it a New Year's resolution to stop.
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.
Some nailbiters find that hypnotherapy is a beneficial treatment.