Objective: To evaluate the prevalence of nail biting in child and adolescent outpatients at a single institution and the chronological relationship between nail biting and tics in patients with Tourette syndrome (TS) with or without attention-deficit hyperactivity disorder (ADHD).
Design: Retrospective observational study.
Setting: Teaching hospital in Taiwan.
Participants: All participants were aged 4-18 years, including 535 patients with TS, 230 patients with provisional tic disorder and 1460 patients without neurological or psychiatric disorders (controls).
Outcome measures: Presence of nail biting, starting age for nail biting and starting age for motor and/or vocal tics.
Results: Nail biting was more commonly observed in patients with TS (56.6%) than in patients with provisional tic disorder (27.4%) or controls (15.0%), regardless of sex (all p<0.020). Nail biting was also more common in patients with TS with ADHD than in those without (75.0% vs 47.6%; p<0.001), but the starting age was significantly later in those with concomitant ADHD than without (5.3 vs 3.8 years; p<0.001). In patients with TS, the onset of nail biting occurred earlier than that of tics, regardless of ADHD status.
Conclusion: Nail biting was more prevalent and occurred earlier than tics in patients with TS, regardless of ADHD status, in the study population.
Keywords: Child & adolescent psychiatry; MENTAL HEALTH; PAEDIATRICS.
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