Onychophagia is defined as chronic nail biting behaviour, which usually starts during childhood. Onychtillomania results from recurrent picking and manicuring of the fingernails and/or toenails, leading to visual shortening of the nails.

Nail biting is considered a nervous habit, regarded as a relatively unconscious behaviour that is repeated out of anxiety, stress or boredom. Some people bite their nails so badly that their fingers bleed or the nails are so stunted that there is almost no nail left.

Apart from the negative aesthetic appearance, when you bite your nails you are constantly transferring bacteria between your mouth and your fingers. This may have an adverse affect on your teeth and gums.

A recent study done by the department of Psychiatry and Department of Dermatology at Wroclaw Medical University , Poland (Jan 2014) examined the prevalence of onychophagia and onychotillomania in young adults and the relationship of these conditions with anxiety disorders.

What they found in a group of 208 students, is that nail biting may occur in moments of stress or anxiety as an attempt to calm down. In some cases nail biting is preceded by a feeling of stress, and that stress may increase if the person tries to resist nail biting. For some people nail biting is an automatic behaviour, they are doing it without thinking about it, especially when engaged in other activities such as reading or watching TV.

The authors have determined that although nail biting is partly related to emotional disturbance and anxiety, only a few studies have shown an association between nail biting and anxiety. The variability of findings they say is due to different methods used in the analysis, as well as different attitudes to anxiety. This study however, did show a statistically significant difference in the prevalence of general anxiety disorder in participants with and without nail biting. An interesting finding in this study was that no single condition or factor is associated with nail biting, or has an influence on such behaviour, but that multiple factors are involved.

For counselling of children or young adults the proposed treatment of nail biting:

Habit reversal includes awareness training, relaxation training, competing response training and contingency management.

So, the frequency of the nail biting could be recorded in order to increase awareness.

Identifying the situations or places in which the nail biting occurs may also help with awareness.

Relaxation training may be useful, especially if anxiety has been identified as a factor.

Finding a behaviour that may be incompatible with nail biting, a competing response as a conscious distraction should be helpful.

Finally, contingent management, offering praise and rewards for achieving non nail biting goals.

Habits usually have functions, identifying the function for an individual may help assess the reasons for maintaining the nail biting habit. It has been suggested that since nail biting may be categorized as an impulse control problem, medication such as SSRI's (anti anxiety/depression) may actually exacerbate the impulse. So far there are no clinical trials that show evidence for the treatment of nail biting behaviour with medication.

As habitual nail biting seems to be a symptom of a more complex psychological state, it has proven to be difficult to treat, it must be remembered that employing all of the above strategies will not yield results in the short term, it may take months to achieve results. If no results are achieved, there is the possibility that management techniques may be more successful as you age.