Psychiatry: Diagnosis, Risk, and Treatment Selection
What this domain tests
The Psychiatry section assesses whether you can move from a clinical presentation to a defensible diagnosis, safety plan, and treatment choice using current diagnostic criteria and psychopharmacology. Expect item stems that combine risk assessment, differential diagnosis, and medication monitoring rather than isolated fact recall. Items often ask for the next best step.
Core rules
- Diagnose by criterion count, duration, and exclusion. Major depressive disorder requires ≥5 depressive symptoms for ≥2 weeks, including depressed mood or anhedonia; exclude lifetime mania/hypomania and substance/medical causes.
- Bipolar I requires at least one manic episode: abnormally elevated, expansive, or irritable mood with increased energy lasting ≥1 week (or hospitalization), plus ≥3 manic symptoms (≥4 if mood is only irritable).
- Schizophrenia requires ≥2 of delusions, hallucinations, disorganized speech, disorganized/catatonic behavior, or negative symptoms during the active phase, with continuous signs for ≥6 months and ≥1 from the first three.
- Delirium is an acute, fluctuating disturbance of attention and awareness; identify and treat the medical cause rather than sedating blindly.
- Ask about suicide directly; assess intent, plan, means, prior attempts, and protective factors. Do not rely on “no-harm contracts.”
- Monitor lithium (renal, thyroid, calcium, level) and antipsychotics (weight, glucose, lipids, prolactin, EPS).
Worked example
A 24-year-old presents with 8 days of decreased need for sleep, pressured speech, grandiosity, and spending sprees. He denies substance use, and thyroid tests are normal. Symptoms cause marked impairment but do not require hospitalization. The duration and symptom count support mania; one manic episode establishes bipolar I disorder, not bipolar II (which requires hypomania and a major depressive episode). Start with a mood stabilizer/antipsychotic, assess suicide risk, and avoid antidepressant monotherapy.
Traps
- Calling irritability alone mania without increased energy or duration.
- Missing hypomania in a patient presenting with depression.
- Using antidepressants alone in bipolar depression without a mood stabilizer.
- Attributing delirium to “anxiety” and missing the medical cause.