Depressed Mood: MCCQE1 Preparation Guide

CanMEDS Role: Medical Expert

As a Canadian physician, you are expected to differentiate between normal sadness, grief, and major depressive episodes, while expertly managing the bio-psycho-social aspects of the patient’s care.

Introduction

Depressed mood is one of the most common presentations in Canadian primary care. For the MCCQE1, candidates must demonstrate the ability to distinguish between Major Depressive Disorder (MDD), Adjustment Disorder, Grief, and depressed mood secondary to medical conditions or substance use.

Understanding the Canadian Network for Mood and Anxiety Treatments (CANMAT) guidelines is essential for high performance on the exam.

MCCQE1 Objectives

When preparing for the MCCQE1, focus on the following key objectives regarding depressed mood:

Data Acquisition:
- Obtain a history of the depressive episode (onset, duration, severity).
- Screen for SIGECAPS symptoms.
- Assess for suicide risk (mandatory in every psychiatric interview).
- Identify substance use or medical conditions mimicking depression.
Diagnosis:
- Apply DSM-5-TR criteria for MDD.
- Differentiate MDD from Bipolar Disorder (screen for mania).
Management:
- Apply the bio-psycho-social model.
- Select appropriate pharmacotherapy based on CANMAT guidelines.
- Determine the need for hospitalization (involuntary admission criteria).

Epidemiology in Canada

Understanding the prevalence helps in pre-test probability assessment:

Lifetime Prevalence: Approximately 11-12% of Canadians will experience MDD in their lifetime.
Gender: Females are affected more frequently than males (approx. 2:1 ratio).
Age: High prevalence in young adults (15-24) and the elderly (often presenting with somatic complaints or cognitive decline/pseudodementia).

Differential Diagnosis

The MCCQE1 often tests your ability to rule out “organic” or medical causes before diagnosing a primary psychiatric disorder.

Psychiatric

MDD, Persistent Depressive Disorder (Dysthymia), Bipolar Disorder (I or II), Adjustment Disorder, Bereavement/Grief.

Clinical Assessment

1. History Taking (The SIGECAPS Mnemonic)

To diagnose a Major Depressive Episode, the patient must have 5 or more symptoms for a 2-week period. One of the symptoms must be Depressed Mood or Anhedonia.

Use the mnemonic SIGECAPS to recall the criteria:


S - Sleep changes (Insomnia or Hypersomnia)
I - Interest (Loss of interest/Anhedonia)
G - Guilt (Worthlessness)
E - Energy (Fatigue)
C - Concentration (Diminished ability to think/focus)
A - Appetite (Weight loss or gain)
P - Psychomotor (Agitation or Retardation)
S - Suicidality (Recurrent thoughts of death)

2. Suicide Risk Assessment

This is a critical station in the CDM (Clinical Decision Making) portion of the MCCQE1 and OSCEs.

Step 1: Ideation

Ask directly: “Have you had thoughts that life is not worth living?” or “Have you had thoughts of ending your life?”

Step 2: Plan

If yes, ask: “Do you have a plan of how you would do it?”

Step 3: Intent & Means

Ask: “Do you intend to act on these thoughts?” and “Do you have access to the means (e.g., firearms, medications)?”

Step 4: Protective Factors

Assess what keeps them alive (e.g., children, religion, pets).

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CRITICAL: If a patient has a specific plan, intent, and access to means, this is a psychiatric emergency requiring immediate safety measures, often involving involuntary admission (Form 1 in Ontario, or provincial equivalent).

3. Screening Tools

PHQ-9 (Patient Health Questionnaire-9): Widely used in Canadian family practice to screen and monitor severity.
Geriatric Depression Scale (GDS): Useful for elderly patients where somatic symptoms may be confounding.

Canadian Guidelines (CANMAT)

The CANMAT 2016 Clinical Guidelines (with 2023 updates) are the standard for MCCQE1.

First-Line Pharmacotherapy

Monotherapy with one of the following is typically first-line for moderate to severe MDD:

SSRIs: Escitalopram, Sertraline, Citalopram, Fluoxetine, Paroxetine.
SNRIs: Duloxetine, Venlafaxine, Desvenlafaxine.
Others: Bupropion (good for low energy/smokers, avoid in seizure history), Mirtazapine (good for insomnia/weight loss).

Psychotherapy

For mild to moderate depression, psychotherapy is considered a first-line treatment, either alone or in combination with medication.

CBT (Cognitive Behavioral Therapy)
IPT (Interpersonal Therapy)

Treatment Algorithm Summary

Step	Intervention	Notes
Step 1	Monotherapy (SSRI/SNRI/Bupropion)	Trial for 4-8 weeks at therapeutic dose.
Step 2	Switch or Augment	If partial response: Augment (e.g., add Aripiprazole or Lithium). If no response: Switch to different class.
Step 3	Combination	Combine antidepressants with different mechanisms.

Key Points to Remember for MCCQE1

Rule out Bipolar: Before starting an antidepressant, always screen for a history of mania/hypomania (“Have you ever had periods where you felt too good, didn’t need sleep, or were very energetic?”). Starting an SSRI in an undiagnosed bipolar patient can precipitate a manic episode.
Elderly Patients: New-onset depression in the elderly requires a workup for organic causes (CT head for malignancy/stroke, MMSE for dementia).
Bereavement: DSM-5 removed the “bereavement exclusion.” You can diagnose MDD within 2 months of the death of a loved one if criteria are met and severity warrants it.
Serotonin Syndrome: Know the triad: Autonomic instability, Altered mental status, Neuromuscular irritability (hyperreflexia/clonus). Distinguish from Neuroleptic Malignant Syndrome (NMS), which features “lead-pipe” rigidity and hyporeflexia.
Labs: Standard workup for new fatigue/depression usually includes CBC (anemia), TSH (hypothyroidism), and Vitamin B12.

Sample Question

Clinical Scenario

A 45-year-old man presents to the family medicine clinic with a 2-month history of “feeling low,” fatigue, and difficulty staying asleep. He reports a 5 kg weight loss during this period and feels that he is “underperforming” at work. He denies any suicidal ideation. His past medical history is unremarkable, and he takes no medications. Physical examination reveals a flat affect but is otherwise normal.

Question

Which one of the following is the most appropriate next step in the management of this patient?

A. Prescribe fluoxetine 20 mg daily
B. Refer immediately to a psychiatrist
C. Order a Thyroid Stimulating Hormone (TSH) level
D. Reassure the patient and schedule a follow-up in 3 months
E. Order a CT scan of the head

Explanation

The correct answer is:

C. Order a Thyroid Stimulating Hormone (TSH) level

Detailed Explanation: While the patient meets several criteria for Major Depressive Disorder (depressed mood, sleep disturbance, weight loss, fatigue), the MCCQE1 emphasizes the importance of ruling out organic (medical) causes of depressive symptoms before confirming a psychiatric diagnosis and initiating psychotropic medication.

Option C is correct: Hypothyroidism is a common, reversible cause of depressive symptoms (fatigue, weight changes, mood changes). Canadian guidelines recommend a basic metabolic workup (TSH, CBC, electrolytes) for new-onset depression to rule out medical mimics.
Option A is incorrect: While fluoxetine is a first-line treatment for MDD, it is premature to start medication without ruling out organic causes (like hypothyroidism) first.
Option B is incorrect: Immediate referral to psychiatry is reserved for complex cases, treatment resistance, or high suicide risk. This patient can be managed in primary care initially.
Option D is incorrect: The patient has significant symptoms impacting function; reassurance alone is insufficient, and a 3-month follow-up is too long.
Option E is incorrect: A CT head is not indicated unless there are focal neurological signs or cognitive deficits suggestive of a structural lesion, which are not present here.

References

Kennedy, S. H., et al. (2016). Canadian Network for Mood and Anxiety Treatments (CANMAT) 2016 Clinical Guidelines for the Management of Adults with Major Depressive Disorder. Canadian Journal of Psychiatry.
American Psychiatric Association. (2022). Diagnostic and Statistical Manual of Mental Disorders (5th ed., text rev.).
Public Health Agency of Canada. (2023). Mood and anxiety disorders in Canada. [Link to PHAC]
Medical Council of Canada. (2023). MCCQE Part I Objectives: Mental Health.