A self-reported instrument for prodromal symptoms of psychosis: testing the clinical validity of the PRIME Screen-Revised (PS-R) in a Japanese population.
OBJECTIVE
Early intervention for psychosis requires an easy, useful assessment instrument to identify subjects with prodromal symptoms at an early stage. The aim of this study was to test the clinical validity of the PRIME Screen-Revised (PS-R), a 12-item self-reported instrument for prodromal symptoms of psychosis, by comparing the results for a non-clinical population with those for a clinical population.


METHODS
The PS-R was administered to 1,024 subjects (496 students and 528 outpatients). Of the 528 patients, 115 were randomly recruited and tested using the Structured Interview for Prodromal Syndromes (SIPS) to determine the concordant validity of the PS-R. The predictive validity of the PS-R was measured by determining the transition rate to psychosis during a 6-month follow-up period.


RESULTS
The specificity and sensitivity of the PS-R, using the SIPS as a gold standard, were 0.74 and 1.00. The concordant validity of the PS-R against the SIPS was 0.43. The predictive validity of the PS-R and the SIPS, defined as the transition rate to psychosis, were 0.11 and 0.25, respectively. None of the patients with negative PS-R results developed psychosis.


CONCLUSIONS
Our findings showed that the PS-R was highly valid and that its usage is feasible in both general practice and clinical settings. This self-reported instrument represents a useful screening tool for alerting clinicians to subjects with psychotic prodromal symptoms.
Kobayashi
Hiroyuki
H
Department of Neuropsychiatry, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-Ku, Tokyo 160-8582, Japan. h-kobayashi@tmh.or.jp
Nemoto
Takahiro
T
Koshikawa
Hiroki
H
Osono
Yasunori
Y
Yamazawa
Ryoko
R
Murakami
Masaaki
M
Kashima
Haruo
H
Mizuno
Masafumi
M
D000293:Adolescent; D000328:Adult; D000553:Ambulatory Care; D044466:Asian People / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening; D010342:Patient Acceptance of Health Care; D010555:Personality Inventory; D011237:Predictive Value of Tests; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data*; D011594:Psychometrics; D011618:Psychotic Disorders / Q000175:diagnosis* / Q000523:psychology; D015203:Reproducibility of Results; D012559:Schizophrenia / Q000175:diagnosis; D012565:Schizophrenic Psychology; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires