Symptom modelling using hypnosis.

Research on psychiatric disorders faces the challenge that symptoms of psychopathology are by their nature elusive. Functional symptoms, hallucinations, delusions, and passivity phenomena involve private changes in experience which are often unpredictable in nature, co-morbid, confounded, and heterogeneous. Hypnosis and experimental suggestion provide a potential means of overcoming these limitations. By eliciting precise, transient alterations in experience under controlled conditions, symptom models created by suggestion in hypnosis allow researchers to probe mechanisms that are otherwise difficult to study, such as disruptions in self-monitoring, agency, and belief evaluation. This chapter reviews the historical and contemporary development of hypnotic symptom modelling, evaluates the methodological debates concerning suggestibility, demand characteristics, and phenomenological characterisation, and considers applications ranging from hallucinations and delusional misidentification to functional neurological symptoms. We conclude that while suggested symptoms do not replicate clinical disorders in full, they provide useful experimental analogues that can bridge laboratory and clinic, refine cognitive theories, and highlight potential therapeutic strategies. Moreover, by linking mechanistic insights from modelling to therapeutic practice, clinical hypnosis and suggestion can potentially alleviate distress in clinical contexts.