Psychiatry/Behavioral · PANCE / PANRE

Obsessive-Compulsive Disorder (OCD)

Intrusive ego-dystonic obsessions and ritualized compulsions consuming >1 hour/day or causing impairment.

Also known as: OCD, obsessive-compulsive disorder

Overview

Presence of obsessions (recurrent, intrusive, unwanted thoughts/images/urges) and/or compulsions (repetitive behaviors or mental acts performed to reduce distress or prevent a feared outcome) that are time-consuming (>1 hour/day) or cause clinically significant distress/impairment.

Epidemiology

Lifetime prevalence ~2-3%. Bimodal onset: childhood/early adolescence (males) and early adulthood (females). Often chronic with waxing/waning course.

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Risk factors

Family history (first-degree relative 4x risk; higher with childhood-onset proband)
Streptococcal infection (PANDAS) in pediatric cases
Adverse childhood experiences, perinatal complications
Comorbid tic disorder, Tourette syndrome

Pathophysiology

Cortico-striato-thalamo-cortical (CSTC) circuit dysfunction with hyperactivity of orbitofrontal cortex, anterior cingulate, and caudate; serotonergic and glutamatergic dysregulation. Heritability ~50%.

Clinical presentation

Symptoms

Common obsession themes: contamination, harm/aggression, symmetry/exactness, taboo (sexual/religious/violent), somatic
Common compulsion themes: washing/cleaning, checking, counting, ordering, mental rituals (e.g., praying, repeating phrases), reassurance seeking
Patients recognize obsessions as their own and excessive (insight varies)
Avoidance of trigger situations (e.g., public restrooms)

Signs / physical exam

Dermatitis or skin damage from washing
Time-consuming routines reported by family
Y-BOCS score >=16 supports moderate symptoms

Differential diagnosis

GAD — Worries are about real-life concerns, not ego-dystonic; no ritualized neutralizing behaviors
Obsessive-compulsive personality disorder — Ego-syntonic perfectionism and rigidity without true obsessions/compulsions
Body dysmorphic disorder — Preoccupation with perceived appearance flaws; compulsive mirror-checking
Hoarding disorder — Difficulty discarding due to perceived need to save items; clutter impairs use of living space
Trichotillomania / excoriation — Repetitive hair-pulling or skin-picking without true obsessions
Tic disorder / Tourette — Premonitory urge with sudden non-purposeful movements; can co-occur with OCD
Psychotic disorder — Obsessions in OCD are recognized as one's own; psychotic delusions are held with full conviction

Diagnostic workup

Diagnostic criteria

DSM-5-TR: Presence of obsessions, compulsions, or both; obsessions are recurrent intrusive thoughts/urges/images causing anxiety, which the person attempts to ignore/suppress or neutralize with another thought or action; compulsions are repetitive behaviors/mental acts the person feels driven to perform in response to an obsession or rigid rule, aimed at preventing or reducing distress, not realistically connected or clearly excessive. Time-consuming (>1 hr/day) or causes significant distress/impairment. Specify level of insight.

Labs

Targeted history; routine labs not required
Throat culture or ASO/anti-DNase B if abrupt pediatric onset (PANDAS suspected)

Imaging

Not routinely indicated

Diagnostic algorithm

Symptom dimension	Typical obsession	Typical compulsion
Contamination	Fear of germs/illness	Washing, cleaning, avoidance
Harm	Fear of harming self/others	Checking, reassurance seeking
Symmetry	Need for things 'just right'	Ordering, counting, repeating
Taboo	Unwanted sexual/violent/religious thoughts	Mental rituals, praying, confession
Hoarding (now separate dx)	Distress at discarding	Saving, acquiring

Common OCD symptom dimensions with paired obsession and compulsion patterns.

Treatment

First-line

Cognitive behavioral therapy with exposure and response prevention (ERP) — most effective intervention
SSRI at higher doses than for depression — fluoxetine, sertraline, fluvoxamine, paroxetine, escitalopram (off-label)
Clomipramine (TCA with strong serotonergic activity) — comparable efficacy; reserved for SSRI nonresponders due to side effects
Combine ERP + SSRI for severe symptoms

Second-line / adjunct

Augmentation with atypical antipsychotic (risperidone, aripiprazole) for SSRI partial response, particularly with comorbid tics
Glutamatergic agents (memantine, N-acetylcysteine) — emerging evidence
Deep brain stimulation for severe, intractable OCD in specialized centers
Intensive residential ERP programs for treatment-resistant cases

Complications

Functional impairment, social isolation, occupational decline
Comorbid depression (~30-50%), anxiety disorders, tic disorders
Skin breakdown from washing rituals
Suicidal ideation in severe disease

PANCE pearls

OCD requires higher SSRI doses than depression (e.g., fluoxetine 40-80 mg, sertraline 150-200 mg) and longer trials (10-12 weeks) before declaring failure.
Insight specifier ranges from good/fair to absent/delusional — does not change diagnosis from OCD to psychosis.
PANDAS: abrupt-onset pediatric OCD or tics temporally linked to streptococcal infection; controversial but recognized entity.
Family accommodation (relatives participating in or enabling rituals) predicts worse outcomes — address in treatment.

References

APA 2007 — American Psychiatric Association Practice Guideline for the Treatment of Patients with Obsessive-Compulsive Disorder (2007)
NICE CG31 — NICE Clinical Guideline 31: OCD and BDD
DSM-5-TR — American Psychiatric Association. DSM-5-TR (2022)
Y-BOCS — Goodman WK et al. The Yale-Brown Obsessive Compulsive Scale. Arch Gen Psychiatry 1989

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