Psychopathology and Clinical Interview / Diagnostic Formulation
Descriptive psychopathology
A candidate must be able to define and distinguish symptoms precisely: delusion (fixed false belief, held with conviction, not shared by culture), overvalued idea, hallucination versus illusion versus pseudohallucination, thought insertion/withdrawal/broadcast, passivity phenomena, formal thought disorder (derailment, loosening, neologism, thought blocking), and catatonic signs. Know the difference between mood-congruent and mood-incongruent psychotic features, and between obsessions (ego-dystonic, resisted) and delusional beliefs.
The interview as a tool
Structure: rapport, open questions, funnel technique, mental state examination (appearance, behaviour, speech, mood and affect, thought form and content, perception, cognition, insight, risk). Screening for risk (self-harm, suicide, harm to others, safeguarding) must be explicit. Collateral history and informant accounts are essential in cognitive and psychotic presentations.
Formulation
A good formulation integrates predisposing, precipitating, perpetuating and protective factors (the 4 Ps), plus a differential diagnosis and a risk formulation. Traps: confusing formulation with diagnosis; forgetting to state the differential; omitting biopsychosocial integration; describing affect as "mood" and vice versa.
Worked rule of thumb
If a belief is shared by the patient's cultural or religious group, do not label it delusional unless it is clearly idiosyncratic in content and context. Always record the exact words used by the patient to support phenomenological claims.