Obsessive Compulsive OCD and Related Disorders

Introduction

Welcome to our comprehensive MCCQE1 preparation guide on Obsessive Compulsive Disorder (OCD) and Related Disorders. This article is tailored for Canadian medical students preparing for the Medical Council of Canada Qualifying Examination Part I (MCCQE1). We'll cover key concepts, Canadian guidelines, and provide practice questions to help you succeed in your exam.

Understanding OCD and Related Disorders

Obsessive Compulsive Disorder (OCD) is a mental health condition characterized by persistent, intrusive thoughts (obsessions) and repetitive behaviors or mental acts (compulsions). In the context of Canadian healthcare, it's crucial to understand the impact of OCD on patients' quality of life and the healthcare system.

Key Features of OCD

Canadian Epidemiology and Impact

Understanding the prevalence and impact of OCD in Canada is crucial for MCCQE1 preparation:

• Prevalence: Approximately 1-2% of the Canadian population is affected by OCD.
• Age of Onset: Typically begins in late adolescence or early adulthood.
• Gender Distribution: Equally common in males and females.
• Economic Impact: OCD costs the Canadian healthcare system an estimated $2.3 billion annually in direct and indirect costs.

Diagnostic Criteria for OCD (DSM-5)

Understanding the diagnostic criteria is essential for MCCQE1 success:

1. Presence of obsessions, compulsions, or both
2. Obsessions or compulsions are time-consuming (>1 hour/day) or cause significant distress/impairment
3. Symptoms are not attributable to the physiological effects of a substance or another medical condition
4. The disturbance is not better explained by another mental disorder

Related Disorders

For MCCQE1 preparation, it's crucial to understand the spectrum of OCD-related disorders:

1. Body Dysmorphic Disorder (BDD)

   • Preoccupation with perceived defects in physical appearance
   • Repetitive behaviors or mental acts in response to appearance concerns

2. Hoarding Disorder

   • Persistent difficulty discarding possessions
   • Accumulation of items, cluttering living areas

3. Trichotillomania (Hair-Pulling Disorder)

   • Recurrent pulling out of one's hair
   • Resulting in hair loss

4. Excoriation (Skin-Picking) Disorder

   • Recurrent skin picking resulting in skin lesions
   • Repeated attempts to decrease or stop skin picking

5. Substance/Medication-Induced Obsessive-Compulsive and Related Disorder

   • Symptoms induced by substance intoxication, withdrawal, or medication use

6. Obsessive-Compulsive and Related Disorder Due to Another Medical Condition

   • Symptoms directly attributable to the physiological effects of another medical condition

Canadian Guidelines for OCD Management

Understanding Canadian guidelines is crucial for MCCQE1 success. The Canadian Clinical Practice Guidelines for the Management of Anxiety, Posttraumatic Stress and Obsessive-Compulsive Disorders provide the following recommendations:

1. First-line Treatment:

   • Cognitive Behavioral Therapy (CBT) with Exposure and Response Prevention (ERP)
   • Selective Serotonin Reuptake Inhibitors (SSRIs)

2. Second-line Treatment:

   • Combination of CBT-ERP and SSRIs
   • Clomipramine (a tricyclic antidepressant)

3. Third-line Treatment:

   • Augmentation with antipsychotics (e.g., risperidone, aripiprazole)
   • Deep Brain Stimulation (for severe, treatment-resistant cases)

Pharmacological Management

For MCCQE1 preparation, understand the key medications used in OCD treatment:

Non-Pharmacological Management

CBT with ERP is the gold standard psychological treatment for OCD in Canada:

1. Cognitive Restructuring: Challenging and modifying dysfunctional beliefs
2. Exposure: Gradual, systematic confrontation with feared stimuli
3. Response Prevention: Refraining from compulsive behaviors
4. Mindfulness-Based Interventions: Increasingly used as an adjunct to CBT

Key Points to Remember for MCCQE1

• OCD affects 1-2% of the Canadian population
• Diagnostic criteria include obsessions, compulsions, time consumption, and distress/impairment
• Related disorders include BDD, hoarding, trichotillomania, and excoriation disorder
• First-line treatments in Canada are CBT-ERP and SSRIs
• Canadian guidelines emphasize a stepped-care approach
• Combination therapy (CBT-ERP + medication) is often used for moderate to severe cases
• Consider cultural factors in assessment and treatment planning

Sample Question

A 25-year-old woman presents to her family physician with concerns about excessive hand washing. She reports spending over 3 hours daily washing her hands due to fears of contamination. This behavior has caused her to be consistently late for work and has led to skin irritation. She acknowledges that her fears are excessive but feels unable to control them. Which of the following is the most appropriate first-line treatment according to Canadian guidelines?

• A. Clomipramine
• B. Fluoxetine
• C. Cognitive Behavioral Therapy with Exposure and Response Prevention
• D. Risperidone
• E. Deep Brain Stimulation

Explanation

The correct answer is:

• C. Cognitive Behavioral Therapy with Exposure and Response Prevention

Explanation: According to Canadian guidelines, Cognitive Behavioral Therapy with Exposure and Response Prevention (CBT-ERP) is considered the first-line treatment for OCD. This non-pharmacological approach has shown high efficacy in managing OCD symptoms and is recommended before or alongside medication. While SSRIs like fluoxetine are also considered first-line, CBT-ERP is often preferred as the initial treatment, especially in cases where the patient's insight is good, as in this scenario. Clomipramine is a second-line treatment, risperidone is used for augmentation in treatment-resistant cases, and Deep Brain Stimulation is reserved for severe, treatment-resistant cases.

References

1. American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.).
2. Katzman, M. A., et al. (2014). Canadian clinical practice guidelines for the management of anxiety, posttraumatic stress and obsessive-compulsive disorders. BMC Psychiatry, 14(Suppl 1), S1.
3. Pauls, D. L., Abramovitch, A., Rauch, S. L., & Geller, D. A. (2014). Obsessive-compulsive disorder: an integrative genetic and neurobiological perspective. Nature Reviews Neuroscience, 15(6), 410-424.
4. Sookman, D., & Steketee, G. (2010). Specialized cognitive behavior therapy for treatment resistant obsessive compulsive disorder. In D. Sookman & R. L. Leahy (Eds.), Treatment resistant anxiety disorders (pp. 31-74). Routledge.
5. Statistics Canada. (2012). Canadian Community Health Survey - Mental Health.