Diagnosing psychotic disorders: validity, reliability and applications of the Diagnostic Interview for Psychosis (DIP). Italian version.
OBJECTIVE
The Diagnostic Interview for Psychoses (DIP) is a comprehensive interview schedule for psychotic disorders, linked to the OPCRIT diagnostic algorithm, bridging the gap between fully structured, lay-administered schedules and semistructured, psychiatrist-administered interviews. Here we describe the validity, reliability and applications of the Italian version of the DIP.


METHODS
The interview was translated into Italian and its content validity tested by back translation. Sixty patients, drawn from among those who contacted the South-Verona Community Mental Health Service, were included in the study. Each patient was first assessed independently by two raters, one of whom conducted the interview, while the other assumed the role of observer. Subsequently (median: 89 days), 44 of these patients were re-interviewed by a third rater, who made an independent assessment. Diagnostic validity was assessed in 18 cases, interviewed with the DIP and using the SCAN as 'gold standard'.


RESULTS
The mean duration of the interview was 37 minutes for the inter-rater interviews and 39 minutes for the retest interviews. Good to excellent inter-rater reliability was demonstrated for both ICD-10 and DSM-IV diagnoses, while in the test-retest reliability pairwise agreement was high for half of the items. Diagnostic validity was good, with twelve out of the 18 DIP-OPCRIT diagnoses (67%) matching the SCAN diagnosis.


CONCLUSIONS
Overall, the results support the reliability and validity of the Italian translation of the DIP. The Italian version will be useful both in routine practice to establish standard reference diagnoses of psychosis and in the research field, where it can be used by academic researchers in clinical trials and epidemiological studies.
Rossi
Alberto
A
Department of Medicine and Public Health, Section of Psychiatry and Clinical Psychology, University of Verona, Verona, Italy. alberto.rossi@univr.it
Morgan
Vera
V
Amaddeo
Francesco
F
Sandri
Marco
M
Grigoletti
Laura
L
Maggioni
Francesca
F
Ferro
Adele
A
Rigon
Elena
E
Donisi
Valeria
V
Venturi
Valeria Vailati
VV
Goria
Fabrizio
F
Skre
Ingunn
I
Tansella
Michele
M
Jablensky
Assen
A
D000341:Affective Disorders, Psychotic / Q000175:diagnosis*; D006801:Humans; D007407:Interviews as Topic; D007558:Italy; D007802:Language; D015588:Observer Variation; D015203:Reproducibility of Results