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Obsessive-compulsive disorder (OCD) and related disorders
In OCD intrusive thoughts that feel alien (obsessions) provoke anxiety, and rituals (compulsions) relieve it briefly and reinforce it; treatment is exposure with response prevention (ERP) and an SSRI at a higher dose and for longer than in depression.
Why it matters in the exam
Exam questions describe a person who checks again and again, washes hands, counts or orders, and ask about the diagnosis, the distinction from obsessive-compulsive personality disorder and the treatment. The key: in OCD the person experiences the thoughts as alien and unwanted (ego-dystonic), and the rituals take a lot of time (more than an hour a day) or cause distress. Insight varies, and some people have poor or absent insight — that is still OCD, not psychosis.
On the treatment side, know that SSRIs in OCD are given at higher doses, and response takes 8–12 weeks. Clomipramine is effective but with more side effects. In resistance a low-dose antipsychotic is added (risperidone or aripiprazole), and in very severe cases deep transcranial magnetic stimulation or deep brain stimulation. The related disorders are asked too: body dysmorphic disorder (BDD), hoarding, trichotillomania (hair pulling) and skin picking. In children, a sudden onset of OCD or tics after a streptococcal infection raises suspicion of PANDAS. There is a known link between OCD, tics and Tourette syndrome. Combining ERP with an SSRI usually works better than either alone, and most patients improve markedly even if not every symptom disappears.
Key points
- Alien obsessions and compulsions that bring brief relief.
- ERP and a high-dose SSRI; judge after 8–12 weeks.
- Resistance → clomipramine or an added antipsychotic.
- Related disorders: body dysmorphic, hoarding, trichotillomania, skin picking.
- Sudden onset in a child after streptococcus → PANDAS.
Summary table
| Disorder | Feature | Treatment | Exam notes |
|---|---|---|---|
| OCD | Obsessions felt as alien and compulsions, more than an hour a day or distress | ERP and a high-dose SSRI, 8–12 weeks to judge | Poor insight is still OCD |
| Resistant OCD | No response to 2 SSRIs at adequate dose and duration | Clomipramine, add risperidone or aripiprazole, deep magnetic stimulation | Continue ERP |
| Body dysmorphic disorder | Preoccupation with an imagined flaw in appearance | CBT and an SSRI | Cosmetic surgery does not help |
| Hoarding | Difficulty discarding possessions, hazardous accumulation | CBT | Poor insight is common |
| Trichotillomania and skin picking | Recurrent hair pulling or skin picking | Habit reversal | Sometimes N-acetylcysteine |
| Obsessive-compulsive personality disorder | Perfectionism and rigidity that feel right | Psychotherapy | No true obsessions or rituals |
Free exam questions
?באיזו מהאבחנות הבאות מספיקה בדיקת מצב נוכחי, ללא צורך במהלך ממושך יותר (the question as examined, in Hebrew)
- א. Conversion Disorder
- ב. Panic Disorder
- ג. Obsessive Compulsive Disorder
- ד. Anorexia Nervosa
מהי ההפרעה הנפשית הנלווית הנפוצה ביותר להפרעת OCD ? (the question as examined, in Hebrew)
- א. הפרעת חרדה חברתית
- ב. טורט
- ג. סכיזופרניה
- ד. דיכאון מז'ורי
Example question from the licensing exam (IMLE)
A 40-year-old female reports avoiding touching objects and after touching something she has to convince herself that she didn’t break it. She looks behind her back many times during the day because she is worried she hadn’t noticed a coin that she dropped or that she stepped on a bug and accidently killed it. Since childhood she felt disgusted of her father and avoided touching or hugging him. Her only desire is to clean her house, which she does every day. What is the most likely diagnosis?
- A. Paranoid personality disorder
- B. Hypochondriasis
- C. Acute and transient paranoid psychosis
- D. Schizophrenia
- E. Obsessive compulsive disorder
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Sources
- DSM-5-TR, American Psychiatric Association, 2022 — Obsessive-Compulsive and Related Disorders
- APA Practice Guideline for the Treatment of Patients With Obsessive-Compulsive Disorder, 2007, guideline watch 2013 — Pharmacotherapy and CBT
- NICE guideline CG31, 2005 — Obsessive-compulsive disorder and body dysmorphic disorder: treatment
- Kaplan and Sadock's Synopsis of Psychiatry, 12th edition (2021) — Obsessive-Compulsive and Related Disorders
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-02. The text may contain errors; when in doubt, check the source.