Psychological Medicine

Original Article

The diagnostic interview for psychoses (DIP): development, reliability and applications

D. J. CASTLE a1, A. JABLENSKY a2c1, J. J. McGRATH a3, V. CARR a4, V. MORGAN a2, A. WATERREUS a2, G. VALURI a2, H. STAIN a2, P. McGUFFIN a5 and A. FARMER a5
a1 University of Melbourne and Mental Health Research Institute, Melbourne, Australia/School of Psychiatry and Clinical Neurosciences, The University of Western Australia, Perth, Australia
a2 The University of Western Australia, Perth, Australia
a3 Queensland Centre for Mental Health Research and University of Queensland, Brisbane, Australia
a4 Centre for Mental Health Studies and University of Newcastle, Newcastle, Australia
a5 MRC Social, Genetic and Developmental Psychiatry Research Centre, Institute of Psychiatry, King's College London, UK

Article author query
castle dj   [PubMed][Google Scholar] 
jablensky a   [PubMed][Google Scholar] 
mcgrath jj   [PubMed][Google Scholar] 
carr v   [PubMed][Google Scholar] 
morgan v   [PubMed][Google Scholar] 
waterreus a   [PubMed][Google Scholar] 
valuri g   [PubMed][Google Scholar] 
stain h   [PubMed][Google Scholar] 
mcguffin p   [PubMed][Google Scholar] 
farmer a   [PubMed][Google Scholar] 


Background. We describe the development, reliability and applications of the Diagnostic Interview for Psychoses (DIP), a comprehensive interview schedule for psychotic disorders.

Method. The DIP is intended for use by interviewers with a clinical background and was designed to occupy the middle ground between fully structured, lay-administered schedules, and semi-structured, psychiatrist-administered interviews. It encompasses four main domains: (a) demographic data; (b) social functioning and disability; (c) a diagnostic module comprising symptoms, signs and past history ratings; and (d) patterns of service utilization and patient-perceived need for services. It generates diagnoses according to several sets of criteria using the OPCRIT computerized diagnostic algorithm and can be administered either on-screen or in a hard-copy format.

Results. The DIP proved easy to use and was well accepted in the field. For the diagnostic module, inter-rater reliability was assessed on 20 cases rated by 24 clinicians: good reliability was demonstrated for both ICD-10 and DSM-III-R diagnoses. Seven cases were interviewed 2–11 weeks apart to determine test–retest reliability, with pairwise agreement of 0·8–1·0 for most items. Diagnostic validity was assessed in 10 cases, interviewed with the DIP and using the SCAN as ‘gold standard’: in nine cases clinical diagnoses were in agreement.

Conclusions. The DIP is suitable for use in large-scale epidemiological studies of psychotic disorders, as well as in smaller studies where time is at a premium. While the diagnostic module stands on its own, the full DIP schedule, covering demography, social functioning and service utilization makes it a versatile multi-purpose tool.

(Published Online September 29 2005)

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