Psychosis: Adult Psychiatry for MCCQE1

Introduction

Psychosis is a clinical syndrome characterized by a loss of contact with reality. For MCCQE1 preparation, it is crucial to understand that psychosis is not a diagnosis in itself but a symptom complex that cuts across various psychiatric, medical, and substance-induced conditions.

In the Canadian healthcare context, the management of psychosis involves a multidisciplinary approach aligning with the CanMEDS framework, particularly the roles of Medical Expert, Communicator, and Health Advocate. Early intervention services, often referred to as First Episode Psychosis (FEP) clinics, are a staple of Canadian psychiatric care.

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Definition: Psychosis involves significant impairment in reality testing, typically manifested by delusions, hallucinations, disorganized speech, and/or disorganized behaviour.

Clinical Presentation

The symptoms of psychosis are classically categorized into positive, negative, and cognitive domains. Understanding these distinctions is vital for differential diagnosis and management questions on the MCCQE1.

Positive Symptoms

“Added” to normal experience:

Delusions: Fixed false beliefs inconsistent with cultural norms (e.g., persecutory, grandiose, referential).
Hallucinations: Sensory perceptions without external stimuli (Auditory is most common in schizophrenia; Visual suggests organic causes).
Disorganized Speech: Loosening of associations, tangentiality, word salad.
Grossly Disorganized Behaviour: Catatonia, agitation, inappropriate affect.

Differential Diagnosis

A systematic approach is required to rule out reversible causes. The MCCQE1 frequently tests the ability to distinguish between primary psychiatric disorders and secondary causes.

Canadian Clinical Pearl

“Medical until proven Psychiatric.” In a Canadian Emergency Department, a patient presenting with new-onset psychosis (especially if <40 years old, visual hallucinations, or abnormal vitals) requires a thorough medical workup to rule out delirium or organic pathology.

Primary vs. Secondary Psychosis

Feature	Primary Psychiatric Disorder (e.g., Schizophrenia)	Secondary (Medical/Substance)
Age of Onset	Typically late teens to mid-20s (Men), late 20s (Women)	Any age (often <13 or >40)
Hallucinations	Predominantly Auditory	Visual, Tactile, Olfactory
Onset Speed	Insidious (prodrome often present)	Acute/Abrupt
Vitals/Physical	Usually Normal	Often Abnormal
Cognition	Alert, oriented (unless severe)	Delirium (waxing/waning consciousness)

Common Etiologies (Mnemonic: VITAMINS)

Vascular: Stroke, SLE vasculitis
Infection: Encephalitis (HSV, Anti-NMDA), HIV, Syphilis, UTI (elderly)
Trauma: TBI
Autoimmune: SLE, Hashimoto’s encephalopathy
Metabolic: Hypoglycemia, Hyperthyroidism, Wilson’s disease, Porphyria
Ingestion/Withdrawal: Cannabis, Stimulants (Methamphetamine/Cocaine), Alcohol withdrawal, Steroids
Neoplasm: Brain tumor
Seizure: Ictal or post-ictal states

Approach to Assessment

Follow these steps to structure your clinical reasoning for MCCQE1 case simulations.

Step 1: Safety and Stabilization

Assess for imminent risk to self or others.

Suicide risk assessment.
Homicide/Violence risk assessment.
Is the patient capable of making decisions? (See Legal Considerations below).
Action: If imminent danger exists, involuntary admission (Form 1 in Ontario, or provincial equivalent) is required.

Step 2: History Taking

Focus on the timeline and associated symptoms.

HPI: Duration, nature of hallucinations, command hallucinations?
Substance Use: Detailed quantification (Cannabis is a major risk factor).
Past Medical History: Seizures, head trauma.
Family History: Schizophrenia, Bipolar Disorder.
Social History: Decline in functioning (school/work).

Step 3: Physical Examination

Look for organic signs.

Vitals: Fever (infection/NMS), Tachycardia (substances/thyroid).
Neurological: Focal deficits, gait abnormalities.
Dermatological: Stigmata of liver disease, needle tracks.

Step 4: Diagnostic Investigations

Standard Canadian workup for First Episode Psychosis (FEP):

Labs: CBC, Electrolytes, Urea/Cr, LFTs, TSH, B12/Folate, Calcium.
Infectious: Syphilis serology (VDRL/RPR), HIV (if risk factors).
Urine: Drug screen (UDS).
Imaging: CT or MRI Head (indicated for first episode to rule out SOL/structural causes).

Schizophrenia Spectrum Disorders

The diagnosis of Schizophrenia requires specific duration and symptom criteria (DSM-5-TR).

Timeline of Psychotic Disorders

Diagnosis	Duration of Symptoms	Functional Decline Required?
Brief Psychotic Disorder	< 1 month (with full return to baseline)	No
Schizophreniform Disorder	1 month to < 6 months	No
Schizophrenia	≥ 6 months (includes prodrome/residual)	Yes

Schizoaffective Disorder

Features of Schizophrenia AND a Major Mood Episode (Depressive or Manic).

Key Distinctor: Delusions or hallucinations must occur for ≥ 2 weeks in the absence of a major mood episode (otherwise it is Mood Disorder with Psychotic Features).

Management

Management must follow the Bio-Psycho-Social model.

1. Pharmacological (Biological)

Antipsychotics are the mainstay. They primarily block Dopamine D2 receptors.

Second-Generation Antipsychotics (SGAs) - Atypical

First-line in Canada due to lower risk of Extrapyramidal Side Effects (EPS).
Examples: Risperidone, Olanzapine, Quetiapine, Aripiprazole, Paliperidone.
Risks: Metabolic syndrome (Weight gain, Diabetes, Dyslipidemia), QTc prolongation.

First-Generation Antipsychotics (FGAs) - Typical

Examples: Haloperidol, Loxapine, Chlorpromazine.
Risks: High risk of EPS (Dystonia, Akathisia, Parkinsonism, Tardive Dyskinesia) and Neuroleptic Malignant Syndrome (NMS).

Clozapine

Reserved for Treatment-Resistant Schizophrenia (failed 2 adequate trials of antipsychotics, one being an SGA).
Safety: Risk of Agranulocytosis. Requires mandatory registration and regular blood monitoring (CBC) in Canada.

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Neuroleptic Malignant Syndrome (NMS): Medical emergency characterized by Fever, Encephalopathy (confusion), Vitals unstable, Elevated CPK/WBC, and Rigidity (lead-pipe).

Treatment: Stop agent, supportive care, Dantrolene/Bromocriptine.

2. Psychosocial

CBT for Psychosis (CBTp): Evidence-based adjunct to medication.
Family Intervention: Reduces relapse rates significantly.
Assertive Community Treatment (ACT): Multidisciplinary teams providing 24/7 community support for severe cases.
Housing/Financial: Assisting with provincial disability support (e.g., ODSP in Ontario, AISH in Alberta).

3. Legal (Canadian Context)

Involuntary Admission: Know the criteria for your province (e.g., “Danger to self, Danger to others, Lack of competence to care for self”).
Community Treatment Orders (CTOs): Mandated outpatient treatment for “revolving door” patients.

Key Points to Remember for MCCQE1

Rule out organic causes: Especially delirium and substance use in new-onset cases.
Cannabis and Psychosis: Heavy cannabis use in adolescence is a significant risk factor for developing schizophrenia.
Suicide Risk: The lifetime risk of suicide in schizophrenia is approximately 5%–10%. Risk is highest early in the illness and during discharge.
Metabolic Monitoring: For patients on SGAs, monitor Weight, BP, Fasting Glucose, and Lipids regularly (Canadian Diabetes Association guidelines).
Tardive Dyskinesia: Long-term side effect (choreoathetoid movements); often irreversible. Switch to Clozapine if severe.

Canadian Guidelines

The Canadian Psychiatric Association (CPA) Clinical Practice Guidelines for Schizophrenia emphasize:

Early detection and intervention (FEP clinics).
Use of SGAs as first-line treatment.
Routine metabolic monitoring.
Use of Long-Acting Injectables (LAIs) to improve adherence.
Clozapine utilization after two failed trials.

Sample Question

Clinical Scenario

A 22-year-old male university student is brought to the Emergency Department by his roommate. The roommate reports that the patient has not attended classes for 6 weeks, rarely leaves his room, and has covered the windows with aluminum foil to “block the government signals.” The patient appears dishevelled and is mumbling to himself. He admits to hearing voices commenting on his actions. He has no significant past medical history. He smokes cannabis occasionally but has not used any in the last week. His vital signs are stable. A urine toxicology screen is negative.

Which one of the following is the most appropriate initial pharmacological management?

Explanation

The correct answer is:

C. Risperidone

Explanation: This patient presents with signs consistent with a First Episode Psychosis (likely Schizophreniform disorder or Schizophrenia, given the 6-week duration).

Choice C (Risperidone): Canadian guidelines recommend Second-Generation Antipsychotics (SGAs) like Risperidone, Olanzapine, or Aripiprazole as first-line therapy for first-episode psychosis due to a lower risk of extrapyramidal side effects (EPS) compared to first-generation agents.
Choice A (Haloperidol): A First-Generation Antipsychotic (FGA). While effective, it is not first-line due to higher rates of EPS (dystonia, parkinsonism) and tardive dyskinesia.
Choice B (Clozapine): Reserved for treatment-resistant schizophrenia (failure of two other antipsychotics). It has severe side effect risks (agranulocytosis, myocarditis).
Choice D (Diazepam): A benzodiazepine. It may be used acutely for agitation but does not treat the underlying psychotic symptoms.
Choice E (Carbamazepine): A mood stabilizer used in Bipolar Disorder, not indicated as monotherapy for acute psychosis.

References

Canadian Psychiatric Association (CPA). (2017). Clinical Practice Guidelines for the Management of Schizophrenia and Schizoaffective Disorder.
American Psychiatric Association. (2022). Diagnostic and Statistical Manual of Mental Disorders (5th ed., text rev.).
Medical Council of Canada. (2023). MCCQE Part I Objectives: Mental Health.
Remington, G., et al. (2017). Guidelines for the Pharmacotherapy of Schizophrenia in Adults. Canadian Journal of Psychiatry.
Centre for Addiction and Mental Health (CAMH). Schizophrenia: Information for Professionals. https://www.camh.ca