Revisiting Shyness and Sociability in Schizophrenia: A Psychometric Examination of Measurement Invariance and Mean Level Differences

Although there is a long and rich empirical history of demonstrating differences on psychological self-report measures between people with schizophrenia and healthy controls, the question of whether both groups respond to psychological measures in the same way has gone largely unexplored. That is, is there measurement equivalence, or invariance, across the samples? To our knowledge, there have been no published studies on measurement equivalency in personality measures across groups diagnosed with and without schizophrenia. Here we examined the question of measurement invariance on two widely used questionnaires assessing temperament, the Cheek and Buss Shyness and Sociability Scales (CBSHY and CBSOC, respectively) between 147 stable adult outpatients with schizophrenia and 147 healthy age- and sex-matched controls. Results supported measurement invariance of the CBSHY and CBSOC across our clinical and non-clinical groups. These findings suggested that stable adult outpatients with schizophrenia and age- and sex-matched controls respond to the shyness and sociability items in the same way. We found that adults with schizophrenia reported higher levels of shyness and lower levels of sociability than healthy controls, consistent with prior studies. Findings are discussed concerning their relevance more broadly to self-report assessments of personality and psychological traits in clinical populations.