In a patient with a six‑month history of spending several hours each day arranging and rearranging furniture to achieve perfect symmetry and experiencing marked distress when prevented, is this phenomenon best classified as an impulse, delusion, compulsion, or obsession?

Classification of Repetitive Furniture Arranging Behavior

This behavior is best classified as a compulsion—specifically, a symmetry-related compulsion driven by the need to achieve "perfect" alignment and a "just right" feeling. 1

Defining the Phenomenon

The patient's repetitive furniture arranging represents a compulsion rather than an obsession, impulse, or delusion based on the following characteristics:

• Compulsions are repetitive behaviors or mental acts that an individual feels driven to perform in response to an obsession or according to rigid rules, or to achieve a sense of "completeness" 1
• The behavior involves repetitive physical acts (arranging furniture) performed according to rigid rules (achieving perfect symmetry) 1
• The patient experiences marked distress when prevented from performing these actions, which is characteristic of compulsions 2

Why This Is NOT the Other Options

Not an Obsession

• Obsessions are repetitive and persistent thoughts, images, impulses, or urges that are intrusive and unwanted 1
• The question describes a behavior (arranging furniture), not intrusive thoughts 2
• While obsessions about symmetry may underlie this behavior, the described phenomenon itself is the behavioral act 1

Not an Impulse

• Impulsive behaviors are ego-syntonic (aligned with personal desires) and performed for gratification, whereas compulsions are ego-dystonic (experienced as unwanted) and performed to reduce anxiety 3, 2
• The patient experiences "significant distress," indicating the behavior is unwanted and anxiety-driven, not gratifying 3
• OCD is explicitly distinguished from impulse-control disorders in diagnostic criteria 3

Not a Delusion

• The patient likely retains insight that the behavior is excessive (though the question doesn't specify insight level) 1
• Delusions would involve fixed false beliefs; this describes a behavioral compulsion 1

Symmetry Compulsion Subtype

This case fits the symmetry symptom dimension of OCD:

• Symmetry concerns are characterized by obsessions about order and exactness, paired with ordering, straightening, and repeating compulsions 1, 2
• Ordering/symmetry/repeating compulsions are frequently performed to achieve a "just right" feeling 1, 4
• The patient's need for "perfect symmetry" and hours spent arranging furniture precisely matches this dimension 1

Clinical Significance Criteria Met

The behavior meets diagnostic thresholds for OCD:

• Time-consuming criterion: Taking more than 1 hour per day indicates functional impairment 3, 2
• The patient spends "hours each day" on this behavior 2
• Clinically significant distress is present when unable to perform the actions 2
• Six-month duration demonstrates chronicity 1

Common Pitfall to Avoid

Do not confuse the compulsion (the arranging behavior) with any underlying obsession (intrusive thoughts about symmetry). 1 While both may be present in OCD, the question specifically asks about the repetitive arranging behavior itself, which is definitionally a compulsion. The compulsion may be performed in response to symmetry obsessions, but the behavioral act described is the compulsion 1, 5