The Negative Symptom Inventory-Psychosis Risk (NSI-PR): Psychometric Validation of the Final 11-Item Version.

Abstract

The lack of psychometrically validated assessment tools designed specifically to assess negative symptoms in individuals at clinical high risk (CHR) for psychosis represents a significant barrier to the early identification and prevention of psychosis. To address this need, the Negative Symptom Inventory-Psychosis Risk (NSI-PR) was developed based on the iterative, data-driven approach recommended by the National Institute of Mental Health consensus conference on negative symptoms. This manuscript reports the results of the second study phase that psychometrically validates the final 11-item version of the scale in data collected across 3 sites. A total of 222 participants (144 CHR and 78 clinical help-seeking controls) completed the NSI-PR, 1 week of ecological momentary assessment (EMA), and additional convergent and discriminant validity measures. Structural analyses replicated the previously reported strong fit for the 5-factor (anhedonia, avolition, asociality, alogia, and blunted affect) and hierarchical structures (2 super-ordinate dimensions and 5 lower-level domains). The 5 domains and 2 dimensions generally demonstrated good internal consistency, temporal stability, and interrater reliability. Convergent validity was demonstrated in relation to the 16-item beta version of the NSI-PR, Structured Interview for Psychosis-risk Syndromes negative subscale, Global Functioning Scale social and role, and EMA measures. Discriminant validity was supported by low correlations with positive, disorganized, and general psychiatric symptoms. Findings indicate the final 11-item version of the NSI-PR has sound psychometric properties. The scale, which is designed specifically for CHR individuals, is brief and appropriate for use in research and clinical contexts. Accompanying training materials have been developed to support its use in multisite trials.