Identification and prediction of clinical high risk of psychosis in Chinese outpatients using two-stage screening.

Two-stage screening, involving a self-rating report, followed by a structured interview, has been proposed for identifying clinical high risk of psychosis (CHR) for nearly two decades. This study used PRIME Screen-Revised (PS-R) and Structured Interview for Prodromal Syndromes (SIPS) to investigate the predictive validity of the two-stage screening. Of 566 participants who completed two-stage screening in this study, 192 were PS-R(-) and 374 were PS-R(+). After being interviewed with SIPS, 112 were rated as CHR(+), 109 were diagnosed with psychosis, and the other 345 individuals were CHR(-). Those who were rated through SIPS as CHR(+) and CHR(-) were followed up within 2 years to observe their clinical outcome. Ninety one (81.3%) CHR(+) and 171 (49.6%) CHR(-) individuals completed the investigation at baseline and the two-year follow-up. The cumulative conversion rate to psychosis was 27.5% in CHR(+) group, but only 1.7% in CHR(-) group, with a significant difference between the two groups (log-rank test, χ2 = 30.07, p < 0.001). In terms of two-stage screening, PS-R(-)/CHR(-), PS-R(-)/CHR(+), and PS-R(+)/CHR(-) groups were viewed as expected negative (EN), and the PS-R(+)/CHR(+) group as expected positive (EP), and the sensitivity and specificity was 64.3% and 79.1%, respectively. Furthermore, Kaplan-Meyer survival analysis showed that EP group were more likely to convert to psychosis than EN group (log-rank test, χ2 = 16.702, p < 0.001). Two-stage screening indeed saves much time and alleviates the workload, but may exclude some target individuals. Optimizing self-report scale, and forming a nurse-doctor-interviewer coalition are likely to improve the use of self-rating report and structured interview.