In this study, we examined the preliminary concurrent validity of a brief version of the Prodromal Questionnaire (PQ-B), a self-report screening measure for psychosis risk syndromes. Adolescents and young adults (N = 141) who presented consecutively for clinical assessment to one of two early psychosis research clinics at the University of California, San Francisco and UC Los Angeles completed the PQ-B and the Structured Interview for Prodromal Syndromes (SIPS) at intake. Endorsement of three or more positive symptoms on the PQ-B differentiated between those with prodromal syndrome and psychotic syndrome diagnoses on the SIPS versus those with no SIPS diagnoses with 89% sensitivity, 58% specificity, and a positive Likelihood Ratio of 2.12. A Distress Score measuring the distress or impairment associated with endorsed positive symptoms increased the specificity to 68%, while retaining similar sensitivity of 88%. Agreement was very similar when participants with psychotic syndromes were excluded from the analyses. These results suggest that the PQ-B may be used as an effective, efficient self-report screen for prodromal psychosis syndromes when followed by diagnostic interview, in a two-stage evaluation process in help-seeking populations.
Bibliographical noteFunding Information:
This work was supported by a Young Investigator award from the National Alliance for Research on Schizophrenia and Depression (NARSAD) and NIH grant K23 MH086618 to Dr. Loewy; a gift from the Lazslo N. Tauber Family Foundation to Dr. Vinogradov; and NIH Grants MH65079 and P50 MH066286 to Dr. Cannon. Additional support was provided by gifts to the UCLA Foundation by Garen and Shari Staglin and the International Mental Health Research Organization. The funding sources had no further role in study design; in the collection, analysis and interpretation of data; in the writing of the report; and in the decision to submit the paper for publication.