What are the essential ingredients of a CBT case conceptualization for voices and delusions in schizophrenia spectrum disorders? A study of expert consensus.

Evidence supports the use of cognitive behavioural therapy (CBT) for the treatment of patients with schizophrenia spectrum disorders. A case conceptualization (CC) (or case formulation) is seen as the keystone of CBT in terms of making sense of a patient's difficulties, to guide and inform such treatment. Despite the importance placed on CC there is no known consensus amongst experts as to the essential ingredients involved in this fundamental process. This study used the Delphi method to establish expert consensus for the essential components of a CC when working to treat auditory hallucinations (voices), and persecutory delusions. An international panel of 78 CBT for psychosis (CBTp) experts from 12 different countries participated in the main stage of this study. This 3-stage process involved producing and rating statements that addressed key areas of CC in terms of: presenting issues, predisposing, precipitating, perpetuating and protective factors. One presenting issue and 6 perpetuating factors were endorsed as essential by >80% of the expert panel. The exact same items were endorsed for both voices, and persecutory delusions. The findings are unique in that a large panel of international experts reached consensus that case conceptualizations (CCs) should be parsimonious and focused on the perpetuating (maintaining) factors to facilitate change. Overall, the proposed recommendations should lead to core guidance for the process of developing CCs, and improvements in training for clinicians that conceptualize voices, and persecutory delusions in CBT for schizophrenia spectrum disorders.