Screening the Community for Individuals at Clinical High Risk (CHR) for Psychosis.

INTRODUCTION

The aim of our study was to assess the performance of the Prodromal Questionnaire-16 (PQ-16) and the Perceptual and Cognitive Aberrations scale (PCA) to screen for clinical high risk for psychosis (CHR) in a sample of nonhelp-seeking subjects from São Paulo, Brazil.

METHODS

Individuals aged 18-35 years were interviewed with the PQ-16 and the PCA. Those with a combined score > 10 on the PQ-16 + PCA were called for assessment with the Structured Interview for Psychosis-Risk Syndromes (SIPS). Seventy-five individuals were deemed as CHR and 99 as healthy comparison; 44 randomly selected individuals (PQ-16 + PCA scores < 10) joined as further controls. All participants had no DSM-5 diagnosis. Scores of the PCA, PQ-16 (total score and distress index), and their combinations were analysed.

RESULTS

All the proposed scorings significantly distinguished between CHR and control subjects. Considering a 7% CHR prevalence in the population, PQ-16 score mathematically showed the best performance (AUC = 0.713), followed by the PQ-16 score + PCA (AUC = 0.701). PQ-16 distress had the worst performance (AUC = 0.642).

CONCLUSIONS

Data provides further evidence for the use of the PQ-16 score as an effective instrument to search for CHR states through active screening in the community. Future research should address its potential in helping CHR identification and thus reducing delays in care and minimising the risk of false positives.