Factors Influencing Nail Biting Habit in Children with ADHD

Abstract

This research aims to identify risk factors for developing nail biting (NB) habits among children with Attention Deficit Hyperactivity Disorder (ADHD).  This study recruited 109 children diagnosed with ADHD. Their ADHD relevant components were assessed by questionnaire, and the subjects were divided into NB or non-NB groups. These two groups were compared for their ADHD subtypes, comorbidity (including Oppositional Defiant Disorder (ODD) and anxiety depression), and acquired family risks.  From statistical analyses, we found that ADHD children with a nail-biting habit were generally younger, and many belonged to the ADHD combined subtype (ADHD-C).  We also noted that many of their parents had  marital discord and poorer stress management skills, compared to the parents of ADHD children without a nail-biting habit. Their mothers were generally older than the mothers of ADHD children lacking a nail-biting habit. Logistical regression confirmed that nail biting among ADHD children was correlated with ADHD-C subtype (OR = 2.73; p = 0.016) and parental marital discord (OR = 5.11; p = 0.007). Further, from comorbidity analyses, a nail-biting habit among ADHD children was associated with maladjustment disorder, and not with anxiety disorder commonly seen in ADHD patients. Therefore, nail biting is a possible indication of the presence of the more severe ADHD-C subtype. Our results imply that a nail biting habit among these ADHD children is more related to insufficient parenting skills, rather than being part of general anxiety symptoms.