Royal Park Multidiagnostic Instrument for Psychosis: Part II. Development, reliability, and validity

The Royal Park Multidiagnostic Instrument for Psychosis is a validity-oriented assessment procedure developed for the acute psychotic episode using serial interviews and multiple information sources. This article describes the development and structure of the RPMIP and reports the findings of an interrater reliability study (n = 50). In addition, results are presented from a study that examined aspects of the procedural validity of the instrument when contrasted with consensus diagnoses made by a team of clinicians applying operational criteria in a less formal way to a common sample of patients (n = 87). Finally, the role of assessment procedures of this type in research into psychiatric disorders is briefly discussed.