Assessing and measuring the construct validity of aberrant salience in psychosis symptomatology

The aberrant salience hypothesis of positive symptom formation refers to the dopaminemediated process of abnormal tagging of typically innocuous stimuli. This process is theorised to be central to development of delusions and is thus important in understanding schizophrenia spectrum disorders, however, operationalisation of aberrant salience measurement has varied across investigators. The Aberrant Salience Inventory (ASI; Cicero, Kerns and McCarthy, 2010), a recent measure of subjectively experienced aberrant salience; shows promising psychometric properties however, as a trait measure, it has limited capacity to capture change across time, thus constraining its clinical applications and research potential. Further, its relationship to positive psychotic symptoms warrants exploration. In response to these limitations, we used the ASI to develop a current state measure of aberrant salience called the Aberrant Salience Inventory Current State (ASICS). Furthermore, we aimed to compare the ASICS factor structure to the original ASI and demonstrate the reliability and validity of the ASICS using theoretically related measures. In Study One, a non-clinical sample of 414 adults completed a battery of measures online including the ASICS, Schizotypal Personality Questionnaire –Brief (Raine and Benishay, 1995), Peters Delusions Inventory (Peters, Joseph, and Garety, 1999), Launay-Slade Hallucinations Scale (Larøi, Marczewski, and Van der Linden, 2004) and Behavioural Inhibition and Behavioural Activation (Carver and White, 1994). In Study Two, a subsample of participants from Study One completed an objective state measure of aberrant and adaptive salience called the Salience attribution test (SAT) (Roiser et al., 2009). Development of the ASI into the ASICS did not affect internal reliability. A confirmatory factor analysis largely replicated the original ASI 5-factor structure. The ASICS not only correlated strongly with the SPQ, but also with measures of subclinical delusions and hallucinations. However the ASICS did not correlate with xi the SAT. We conclude that the ASICS replicates measurement of the original ASI constructs and can now be further explored in clinical populations.

Submission note: A thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Psychology in Clinical Psychology to the School of Psychological Science, Faculty of Science, Technology and Engineering, La Trobe University, Bundoora.