General Adult Psychiatry: Classification, Course and Risk
Core concepts
Candidates must be fluent in the descriptive, symptom-based approach of ICD and DSM: syndromes are defined by symptom clusters, duration, and functional impact rather than presumed aetiology. Know the boundary criteria that separate schizophrenia from schizophreniform and brief psychotic disorder (duration), bipolar I from bipolar II (manic vs hypomanic episodes), and major depression from persistent depressive disorder (severity and chronicity). Understand the stress-vulnerability model, the role of expressed emotion, and the difference between incidence, prevalence, and treated prevalence.
Traps
Questions often hinge on duration thresholds and on exclusion rules (substance/medical causation, bereavement caveats). Another common trap is confusing risk factors with causal mechanisms, or confusing an epidemiological association with a screening test's properties. Be precise about what a rating scale measures (symptom severity) versus what it diagnoses (it does not).
Worked example
A 24-year-old presents with 3 weeks of persecutory delusions, auditory hallucinations, and decline in function, with no mood episode and no substance use. Duration under one month with full return to baseline suggests brief psychotic disorder; one to six months suggests schizophreniform disorder; beyond six months, schizophrenia. The rule of thumb: establish the timeline first, then check exclusions, then assess functional decline.
Key points for revision
Use the timeline as an anchor for every psychotic and mood question.