Psychopathology and Diagnostic Classification
Core concepts
Know the classical symptom definitions precisely, because examiners test fine distinctions. A delusion is a fixed false belief held with conviction despite evidence and not shared by one's culture; a delusional perception is a true perception given a new, delusional meaning (Schneiderian). Passivity phenomena (made feelings, impulses, actions) and thought insertion/withdrawal/broadcast are first-rank. Distinguish illusions (misperception of a real stimulus) from hallucinations (perception without stimulus); pseudohallucinations are located in inner subjective space.
Understand the form vs content distinction: formal thought disorder concerns the structure of thinking (derailment, loosening of associations, neologisms), whereas delusions concern content. Know flight of ideas (bipolar, with pressure and distractibility) versus circumstantiality (eventually reaches the goal) versus tangentiality (never reaches it).
Classification
Memorise the architecture of ICD-11 and DSM-5-TR: both are operationalised, but ICD-11 uses a dimensional, lifespan-integrated structure and drops the classic subtypes of schizophrenia. Know that duration criteria differ (schizophrenia: 6 months in DSM-5, 1 month in ICD-11).
Traps
- Calling a culturally sanctioned belief a delusion.
- Confusing obsession (ego-dystonic, resisted) with delusion (ego-syntonic, no resistance).
- Mixing up depersonalisation (self) and derealisation (world).
Rule of thumb
Before labelling a symptom pathological, run the three E's: is it Evidence-resistant, Ego-syntonic, and Experientially abnormal for the person's culture?