A host of research efforts both in America and Europe sought to ascertain if in fact nail biting was linked to mental illness in one form or another. Most people would have anticipated they found a high prevalence of nail biting among the mentally disordered; however, they found that nail biting, in and of itself, is not systematic of any form of mental disorder or maladjustment.

Nail biting crosses all national borders, genders, and both social and economic lines and may also originate from a primal need for self-grooming. It affects both the nails and the cuticles; with greater potential harm caused via infection to the cuticle and nail biting tends to be a private affair, and is a relatively isolated form of self-indulgence.

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