The construct validity of the Inventory of Psychotic-Like Anomalous Self-Experiences (IPASE) as a measure of minimal self-disturbance: Preliminary data

Abstract

Aim: The Inventory of Psychotic-Like Anomalous Self-Experiences (IPASE) is a self-report measure of minimal self-disturbance. The aim of the current report was to assess the construct validity of the scale by examining its convergent validity with the gold-standard measure of minimal self-disturbance, the Examination of Anomalous Self-Experience (EASE), and its discriminant validity.

Method: The sample consisted of 46 participants (21 ultra-high risk for psychosis patients, 14 first episode psychosis patients, 11 healthy controls). Correlations between the clinical instruments were examined.

Results: The IPASE correlated strongly with general psychopathology and positive psychotic symptoms, moderately with negative symptoms, and weakly with manic symptoms. The strongest correlation (r = 0.92) was apparent between IPASE and EASE total scores.

Conclusion: These preliminary data indicate construct validity of the IPASE, demonstrating both convergent and discriminant validity. The IPASE may be suitable as a screener measure for minimal self-disturbance, but should not be used as a replacement to measure the construct of minimal self-disturbance, which requires considerable psychopathological sophistication.

Keywords: phenomenology; prodrome; psychometrics; psychopathology; ultra-high risk.