[The Basel Screening Instrument for Psychosis (BSIP): development, structure, reliability and validity].
BACKGROUND
Early detection of psychosis is of growing clinical importance. So far there is, however, no screening instrument for detecting individuals with beginning psychosis in the atypical early stages of the disease with sufficient validity. We have therefore developed the Basel Screening Instrument for Psychosis (BSIP) and tested its feasibility, interrater-reliability and validity.


OBJECTIVE
Aim of this paper is to describe the development and structure of the instrument, as well as to report the results of the studies on reliability and validity.


METHODS
The instrument was developed based on a comprehensive search of literature on the most important risk factors and early signs of schizophrenic psychoses. The interraterreliability study was conducted on 24 psychiatric cases. Validity was tested based on 206 individuals referred to our early detection clinic from 3/1/2000 until 2/28/2003.


RESULTS
We identified seven categories of relevance for early detection of psychosis and used them to construct a semistructured interview. Interrater-reliability for high risk individuals was high (Kappa .87). Predictive validity was comparable to other, more comprehensive instruments: 16 (32 %) of 50 individuals classified as being at risk for psychosis by the BSIP have in fact developed frank psychosis within an follow-up period of two to five years.


CONCLUSIONS
The BSIP is the first screening instrument for the early detection of psychosis which has been validated based on transition to psychosis. The BSIP is easy to use by experienced psychiatrists and has a very good interrater-reliability and predictive validity.
Riecher-Rössler
A
A
Psychiatrische Poliklinik, Universitätsspital Basel. ariecher@uhbs.ch
Aston
J
J
Ventura
J
J
Merlo
M
M
Borgwardt
S
S
Gschwandtner
U
U
Stieglitz
R-D
RD
D000328:Adult; D014150:Antipsychotic Agents / Q000627:therapeutic use; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D011569:Psychiatric Status Rating Scales / Q000592:standards*; D011618:Psychotic Disorders / Q000175:diagnosis* / Q000188:drug therapy / Q000523:psychology*; D015203:Reproducibility of Results; D012307:Risk Factors; D012559:Schizophrenia / Q000175:diagnosis; D012565:Schizophrenic Psychology; D009626:Terminology as Topic
D014150:Antipsychotic Agents