The diagnostic interview for psychoses (DIP): development, reliability and applications.
BACKGROUND
We describe the development, reliability and applications of the Diagnostic Interview for Psychoses (DIP), a comprehensive interview schedule for psychotic disorders.


METHODS
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.
Castle
D J
DJ
University of Melbourne and Mental Health Research Institute, Melbourne, Australia.
Jablensky
A
A
McGrath
J J
JJ
Carr
V
V
Morgan
V
V
Waterreus
A
A
Valuri
G
G
Stain
H
H
McGuffin
P
P
Farmer
A
A
D003710:Demography; D039721:Diagnostic and Statistical Manual of Mental Disorders; D006801:Humans; D038801:International Classification of Diseases; D007406:Interview, Psychological; D011618:Psychotic Disorders / Q000175:diagnosis*; D015203:Reproducibility of Results