Form (process)
Maps onto observed speech: circumstantiality (over‑inclusive, returns), tangentiality (departs, doesn't return), flight of ideas (rapid, connected shifts + pressure → mania), loosening/derailment/word salad (breakdown of associative links → schizophrenia‑spectrum), thought block (abrupt cessation). Form is your window onto the underlying state before content is even discussed.
Content
- Delusion: fixed, false, idiosyncratic belief, held against evidence, outside cultural norms. Characterise by theme (persecutory, grandiose, referential, jealous/Othello, guilt, nihilistic, somatic, control), conviction (a spectrum — track it to measure response), systematisation, bizarreness, and mood congruence (congruent → affective psychosis; incongruent/bizarre → schizophrenia‑spectrum, though not absolutely).
- Over‑valued idea and obsession sit between normal and delusional — distinguished by resistance, insight, and ego‑dystonia.
Passivity / thought‑possession phenomena (high specificity)
A disturbance of the boundary of the self:
- Thought insertion — thoughts experienced as not one's own, implanted.
- Thought withdrawal — thoughts removed by an external agency.
- Thought broadcasting — thoughts accessible to others.
- (With made feelings/impulses/acts and somatic passivity, these are the first‑rank symptoms — historically weighted toward schizophrenia, but not pathognomonic: they occur in affective psychosis and organic states, so use as pointers, not proof.)
Discriminators
- Passivity vs obsession: passivity = loss of ownership/agency (psychosis); obsession = unwanted but recognised as self‑generated (OCD).
- Flight of ideas vs loosening: connections are understandable in flight of ideas (mania), lost in loosening (schizophrenia).
Pitfalls
- Treating first‑rank symptoms as diagnostic of schizophrenia — DSM‑5 deliberately removed their special status for this reason.
- Missing that a "delusion" fully congruent with a severe mood state is pointing you at affective psychosis, which changes treatment.
Pearls
- 🎯 Ownership is the tell. Loss of thought ownership → psychosis; retained ownership with resistance → OCD‑spectrum.
- 🩺 Quantify conviction at baseline; shrinking conviction is an early, sensitive marker of antipsychotic response.
Next → Assemble perception + thought + behaviour into the syndrome of psychosis and its differential (Concept 7).