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.
Try two board-style Obsessive-Compulsive Disorder questions
Real questions from the FirstPassPA bank, with the full explanation. Pick an answer — no signup, no email.
Question 1PsychiatryEasy
A 22-year-old college student has a 4-month history of intrusive, unwanted thoughts about contamination and harming others that he recognizes as irrational. He performs elaborate hand-washing rituals (30+ minutes daily) and avoids kitchens to reduce anxiety. His grades have declined. Which of the following is the most appropriate first-line psychotherapy?
AExposure and response prevention
BTrauma-focused cognitive behavioral therapy
CSupportive psychotherapy
DDialectical behavior therapy
Reveal answer & full explanation
Correct answer: A — Exposure and response prevention
AExposure and response prevention✓
BTrauma-focused cognitive behavioral therapy
CSupportive psychotherapy
DDialectical behavior therapy
Why Exposure and response prevention is correct
Obsessive-compulsive disorder (OCD) is characterized by recurrent ego-dystonic intrusive obsessions plus compulsions performed to reduce anxiety; recognition of irrationality distinguishes OCD from psychotic disorders.
Exposure and response prevention (ERP) is the most effective psychotherapy: graded exposure to feared stimuli while preventing the compulsive response.
Combined ERP plus an SSRI is superior to either alone.
Why the others are wrong
Trauma-focused cognitive behavioral therapy — the evidence-based treatment for PTSD, not OCD (confused-with trauma exposure).
Supportive psychotherapy — lacks the specific exposure mechanism required to treat OCD and is not first-line (right-concept-wrong-modality).
Dialectical behavior therapy — first-line for borderline personality disorder and emotion dysregulation, not OCD (premature closure).
Additional high-yield points
Pharmacotherapy: selective serotonin reuptake inhibitors (SSRIs) at higher doses than for depression — e.g., sertraline up to 200 mg, fluoxetine, fluvoxamine, paroxetine, escitalopram.
Clomipramine is effective but limited by side effects.
Antipsychotic augmentation (risperidone, aripiprazole) for refractory cases.
Deep brain stimulation (FDA humanitarian device exemption (HDE)) is reserved for severe treatment-refractory OCD.
Question 2PsychiatryMedium
A 19-year-old man has 5 months of intrusive contamination fears and handwashing rituals that now consume 2-3 hours each day, which he acknowledges are excessive. The compulsions have caused him to drop out of college. He has never been treated. Which of the following initial treatment strategies has the strongest evidence base for his condition?
ASSRI plus exposure and response prevention
BSSRI plus clonazepam
CLow-dose olanzapine plus supportive counseling
DSupportive psychotherapy alone
Reveal answer & full explanation
Correct answer: A — SSRI plus exposure and response prevention
ASSRI plus exposure and response prevention✓
BSSRI plus clonazepam
CLow-dose olanzapine plus supportive counseling
DSupportive psychotherapy alone
Why SSRI plus exposure and response prevention is correct
This patient meets criteria for obsessive-compulsive disorder (OCD): time-consuming obsessions and compulsions he recognizes as excessive that impair functioning (dropped out of college)
The best-supported first-line treatment combines a selective serotonin reuptake inhibitor (SSRI) — often at higher doses than used for depression — with exposure and response prevention (ERP)
ERP is the specific cognitive-behavioral technique in which the patient is exposed to feared triggers while refraining from the compulsive ritual
Combined SSRI plus ERP is superior to either modality alone
Why the others are wrong
SSRI plus clonazepam — benzodiazepines do not treat the core obsessions and tend to reinforce avoidance, so they are not part of first-line OCD therapy (confused-with anxiety adjunct)
Low-dose olanzapine plus supportive counseling — antipsychotics are reserved as augmentation for refractory cases, not initial monotherapy in a treatment-naive patient (right-concept-wrong-step)
Supportive psychotherapy alone — generic counseling that omits exposure and response prevention lacks the active therapeutic ingredient for OCD (anchoring on nonspecific talk therapy)
🔒 Free preview limit reached
Keep reading — start your free trial
You've read your 2 free diagnosis previews. Create your free account to unlock the full Obsessive-Compulsive Disorder (OCD) outline — plus all 514 diagnoses, 6,500+ board-style questions, flashcards, and an AI tutor. Your 7-day free trial includes everything, and there's no credit card required.
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
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
Educational use only. This outline is a study aid for PA students and is not medical advice or a substitute for clinical judgment. FirstPassPA is an independent study tool and is not affiliated with, endorsed by, or sponsored by NCCPA or PAEA. PANCE® and PANRE® are registered trademarks of the National Commission on Certification of Physician Assistants; End of Rotation™ is a program of the Physician Assistant Education Association.