Onychophagia in Obsessive-Compulsive Disorder (OCD): Prevalence and Clinical Characterisation

Area of Science:

• Clinical Psychiatry
• Neuroscience
• Behavioral Disorders

Background:

• Onychophagia, or nail-biting, is a repetitive behavior disorder often seen in clinical psychiatry.
• The intersection of obsessive-compulsive disorder (OCD) and onychophagia has been underexplored.
• Understanding this comorbidity is crucial for identifying specific clinical phenotypes.

Purpose of the Study:

• To investigate the prevalence and clinical characteristics of onychophagia in patients diagnosed with OCD.
• To explore potential associations between onychophagia, OCD, and other psychiatric conditions, particularly autism spectrum disorder (ASD).
• To highlight clinical implications for screening and diagnosis in this patient population.

Main Methods:

• A cross-sectional study involving 603 adult patients (≥18 years) with a primary diagnosis of OCD (DSM-5) and moderate severity (Yale-Brown Obsessive-Compulsive Scale score ≥16).
• Patients were recruited from the Department of Neuroscience at the University of Turin.
• Data analysis was conducted using JASP statistical software, with statistical significance set at p < 0.05.

Main Results:

• Onychophagia was identified in 52 out of 603 OCD patients, yielding a prevalence of 8.6% (95% CI: 6.5-11.2%).
• Patients with OCD and onychophagia exhibited distinct clinical features compared to those with OCD alone.
• A significantly higher prevalence of autism spectrum disorder (ASD) was observed in the OCD with onychophagia group (96.2%) versus the OCD without onychophagia group (18.0%).

Conclusions:

• Onychophagia is a relatively common comorbidity in patients with OCD, affecting nearly one in ten individuals.
• The co-occurrence of OCD and onychophagia may indicate a specific clinical phenotype.
• The extremely high rate of ASD in patients with OCD and onychophagia underscores the importance of screening for autism in this cohort.