Classification of Psychotherapy Interventions for People with Schizophrenia: Development of the Nottingham Classification of Psychotherapies

Background Currently, there is no accepted system for the classification of psychotherapies for application within systematic reviews is timely. Objective To devise a system for classification of psychotherapy interventions - for use, initially, in systematic reviews. Methods Cochrane Schizophrenia's Register used as the source of RCTs. After being piloted and refined at least twice, finally we applied it to all relevant trials within the register. Basic statistical data already held within the register were extracted and used to calculate the distribution of schizophrenia research by form of psychotherapy. Findings The final classification system consisted of six definable broad 'boughs' two of which were further subdivided into 'branches'. The taxonomy accommodated all psychotherapy interventions described in the Register. Of the initial 1645 intervention categories within the Register, after careful recoding, 539 (33%) were psychotherapies (234 coded as 'Thought/Action' (cognitive & behavioural) - 1495 studies; 135 'Cognitive Functioning' - 652 studies; 113 'Social' - 684 studies; 55 'Humanistic' - 272 studies; 23 'Psychoanalytic/dynamic' - 40 studies; and 63 'Other' - 387 studies). For people with schizophrenia, across categories, the average size of psychotherapy trial is small (107) but there are notable and important exceptions. Conclusion We reported a practical method for categorising psychotherapy interventions in evaluative studies with applications beyond schizophrenia. A move towards consensus on the classification and reporting of psychotherapies is needed. Clinical Implications This classification can help the clinicians, clinical practice guideline developers, and evidence synthesis experts to recognise and compare the interventions from same or different classes.