Neurocognitive Findings in Onychophagia (Pathological Nail Biting)

Psychiatr Q. 2017 Dec;88(4):747-753. doi: 10.1007/s11126-017-9496-9.


A notable number of people struggle to control the desire to bite their nails, resulting in impairment and distress. Understanding this behavior and the inability to control it has received little research attention. One possible mechanism to understand nail biting is through the use of neurocognitive assessments. Neurocognitive assessments of pathological nail biting, however, are lacking. This analysis assesses the clinical presentation and neurocognitive profile of adults with nail biting relative to participants without nail biting. A total of 87 participants (aged 18-29 years) were recruited for a study on nail biting in young adults. Participants completed diagnostic, self-report, and neurocognitive measures which assessed two cognitive domains - motor impulsivity and cognitive flexibility. In the sample, 34 participants reported current nail biting. The nail biting group showed no significant differences in impulsivity or cognitive flexibility compared to the healthy controls. The lack of association between nail biting and cognitive deficits suggests that perhaps identifying meaningful subtypes of nail biting that reflect distinct pathology from normal grooming behavior may be important.

Keywords: Body-focused repetitive behavior disorder; Cognition; Nail biting; Neuropsychological tests; Obsessive-compulsive and related disorders.

MeSH terms

  • Adolescent
  • Adult
  • Cognitive Dysfunction / etiology
  • Cognitive Dysfunction / physiopathology*
  • Disruptive, Impulse Control, and Conduct Disorders / complications
  • Disruptive, Impulse Control, and Conduct Disorders / physiopathology*
  • Executive Function / physiology*
  • Female
  • Humans
  • Impulsive Behavior / physiology*
  • Male
  • Nail Biting*
  • Young Adult