Pharmacotherapy for OCD and Related Disorders

SSRIs in OCD - SSRI Superstars

• First-line pharmacotherapy for OCD.
• Mechanism: Serotonin reuptake inhibition.
• Key: Higher doses & longer duration vs. depression.
  • Fluvoxamine: up to 300mg/day
  • Fluoxetine: 40-80mg/day
  • Sertraline: up to 200mg/day (can ↑ to 400mg)
  • Paroxetine: up to 60mg/day
  • Citalopram: 40-60mg/day (ECG if >40mg)
  • Escitalopram: 20-30mg/day (can ↑ to 40mg)
• Full trial: 10-12 weeks at maximum tolerated dose.
• Response: Gradual; counsel patience & adherence.
• 📌 Mnemonic: For OCD, SSRIs Soar Higher, Linger Longer

⭐ SSRIs are first-line for OCD, often requiring higher doses (e.g., fluoxetine 40-80mg/day) and longer trial periods (at least 10-12 weeks at maximum tolerated dose) compared to their use in depression.

Clomipramine & Alternatives - TCA Titan & Tactics

• Clomipramine (Anafranil): Tricyclic Antidepressant (TCA); potent Serotonin Reuptake Inhibitor (SRI).
  • Primary Use: OCD, especially severe or SSRI-refractory cases.
  • Dosage: Titrate slowly up to 250mg/day.
  • ⚠️ Critical Monitoring: Baseline and regular ECGs due to cardiotoxicity (QT prolongation, arrhythmias).
  • Common Side Effects:
    • Anticholinergic (dry mouth, constipation).
    • Antihistaminic (sedation, weight gain).
    • Orthostatic hypotension.
    • Lowers seizure threshold.
  • 📌 Mnemonic: "Clomi-prays-a-mean-serotonin-game, but watch the heart!"

⭐ Clomipramine, a tricyclic antidepressant, is often considered one of the most effective pharmacological treatments for OCD, but its use is limited by a greater side-effect burden compared to SSRIs.

Treatment-Resistant OCD - Augment & Attack

• TR-OCD: Inadequate response to ≥2 SSRIs (adequate dose & duration, e.g., Fluoxetine up to 80mg/day for 12 weeks).
• Augmentation Strategies (add to current SSRI):
  • Atypical Antipsychotics (APs):
    • Risperidone 0.5-2mg/day (most evidence)
    • Aripiprazole 2-10mg/day
    • Olanzapine, Quetiapine are alternatives.
  • Clomipramine: Potent SRI; add if not used or switch. Max dose 250mg/day.
  • Other options: Memantine, Ondansetron, Topiramate, N-acetylcysteine (NAC).
• Non-pharmacological: Intensify CBT (Exposure and Response Prevention - ERP).

⭐ Augmentation of SSRIs with atypical antipsychotics (e.g., risperidone, aripiprazole) is an evidence-based strategy for treatment-resistant OCD.

OCRDs Pharmacotherapy - Beyond Obsessions

• Body Dysmorphic Disorder (BDD):
  • SSRIs first-line; higher doses often needed (similar to OCD).
• Hoarding Disorder:
  • SSRIs, venlafaxine; modest efficacy. Augmentation often considered.
• Trichotillomania & Excoriation Disorder:
  • N-acetylcysteine (600-3000 mg/day) promising as glutamatergic modulator.
  • Clomipramine; SSRIs less effective. Consider naltrexone.

⭐ While SSRIs are first-line for Body Dysmorphic Disorder (BDD), N-acetylcysteine (NAC) has shown promise as a glutamatergic modulator in Trichotillomania and Excoriation Disorder.

High‑Yield Points - ⚡ Biggest Takeaways

• SSRIs are first-line for OCD; higher doses and longer trials (8-12 weeks) are often required.
• Clomipramine (TCA) is highly effective for OCD, especially severe cases, but carries more side effects.
• Augmentation with atypical antipsychotics (e.g., risperidone) is used for treatment-resistant OCD.
• Body Dysmorphic Disorder (BDD) and Hoarding Disorder also respond to SSRIs, frequently needing higher doses.
• For Trichotillomania/Excoriation Disorder, N-acetylcysteine or Habit Reversal Therapy (HRT) are preferred; SSRIs show limited efficacy.