Are there any conditions besides Lesch-Nyhan Syndrome and Smith-Magenis Syndrome (SMS) associated with compulsive nail picking?

Conditions Associated with Compulsive Nail Picking Beyond Lesch-Nyhan and Smith-Magenis Syndromes

Yes, several other conditions beyond Lesch-Nyhan Syndrome and Smith-Magenis Syndrome have been reported to cause compulsive nail picking, with Obsessive-Compulsive Disorder (OCD) and Body-Focused Repetitive Behavior Disorders being the most significant. 1, 2

Primary Conditions Associated with Nail Picking

1. Onychotillomania (Nail Picking Disorder)

• Characterized by excessive picking or pulling at finger or toenails
• Considered a body-focused repetitive behavior disorder within the obsessive-compulsive and related disorders (OCRDs) category
• Often occurs automatically, outside of full awareness 2
• May cause significant nail destruction and distress

2. Obsessive-Compulsive Disorder (OCD)

• Nail picking can manifest as a compulsion in OCD
• Usually performed deliberately in response to obsessions
• Often accompanied by anxiety and distress before the behavior
• May be related to contamination concerns or symmetry obsessions 1

3. Body-Focused Repetitive Behavior Disorders

• Trichotillomania (hair-pulling disorder) often co-occurs with nail picking
• Excoriation disorder (skin-picking) frequently presents alongside nail picking
• These conditions share similar neurobiological mechanisms 3, 4

Related Conditions with Nail Picking Features

1. Onychophagia (Nail Biting)

• Closely related to nail picking but involves biting rather than picking
• Affects up to 46.9% of young adults 5
• Can exist on a spectrum from mild to severe
• Often considered part of the OCD spectrum 6

2. Attention Deficit Hyperactivity Disorder (ADHD)

• High comorbidity with nail picking/biting behaviors
• 74.6% of children with nail biting in one clinical sample had ADHD 7
• May represent impulsivity or self-stimulatory behavior

3. Anxiety Disorders

• Separation anxiety disorder (20.6% comorbidity with nail biting)
• General anxiety disorders frequently co-occur with nail picking behaviors 7

4. Other Comorbid Conditions

• Oppositional defiant disorder (36% comorbidity)
• Tic disorders (12.7% comorbidity)
• Enuresis (15.6% comorbidity) 7

Diagnostic Approach for Nail Picking

When evaluating nail picking behavior, assess for:

1. Awareness level: Automatic (unconscious) vs. focused (deliberate) picking
2. Triggers: Sensory discomfort, anxiety, boredom, or specific obsessions
3. Associated behaviors: Other body-focused repetitive behaviors
4. Family history: Parental psychiatric disorders (56.8% of mothers and 45.9% of fathers of children with nail biting have psychiatric disorders) 7

Treatment Considerations

Treatment should target the underlying condition:

• For OCD-related nail picking: Serotonin reuptake inhibitors and cognitive-behavioral therapy 1, 6
• For body-focused repetitive behaviors: Habit reversal training and awareness training 3
• For severe cases: N-acetylcysteine has shown promise by modulating glutamatergic pathways 4

Clinical Pearls

• Nail picking is often underreported and undertreated despite significant impact on quality of life
• The behavior often begins in childhood but can persist into adulthood
• Distinguishing between automatic and focused picking is crucial for treatment selection
• Comorbid psychiatric conditions are common and should be addressed simultaneously

Remember that nail picking represents a spectrum of severity and may require different treatment approaches depending on the underlying cause and associated conditions.