Background: A key process in Cognitive Therapy (CT) is the development and sharing of a formulation. How clinicians develop formulations is under-researched, particularly in working with people with psychosis.
Aims: This study investigated agreement between clinicians, when conceptualizing an individual's psychotic beliefs. It also explored whether agreement was dependent on qualifications and experience.
Method: Eighty-two clinicians watched a video of an individual with delusional beliefs, and were asked to provide formulations using a CT template. These were compared with a "benchmark" formulation provided by three experts.
Results: There was good agreement for overt behaviours, emotions, and some aspects of early experience. However, identification of theory driven components such as core beliefs or assumptions was poorer. Greater clinical experience improved the agreement with the benchmark formulation overall, and greater CT specific experience improved formulation of the theory driven items. The more experience a clinician had of working with people with psychosis the lower the rate of agreement with the expert formulation.
Conclusions: Formulation of delusional beliefs from a cognitive perspective is dependant on overall experience in cognitive therapy and not knowledge of psychosis, which may hinder performance. The implications for training in CT and psycho-social interventions are considered.