Self-reported cognitive distortions in the psychosis continuum: A Polish 18-item version of the Davos Assessment of Cognitive Biases Scale (DACOBS-18)

Aim: The aim of this study was to provide a short version of the Davos Assessment of Cognitive Biases Scale (DACOBS), which is a self-report tool to assess cognitive distortions related to psychosis. Methods: A principal component analysis (PCA) was conducted on a large non-clinical sample (n = 1207) and cross-validated with a confirmatory factor analysis on an independent non-clinical sample (n = 653). Discriminative validity was performed by contrasting the high risk for psychosis non-clinical sample (n = 63), low risk for psychosis non-clinical sample (n = 152), patients with schizophrenia (n = 105), and patients with depression (n = 56). Correlations between symptoms, cognitive functions, source monitoring deficits, and jumping to conclusions were performed among a subgroup of patients with schizophrenia. Results: An 18-item scale (DACOBS-18) with a four-factor solution was established. Internal consistency (alpha = 0.84) and test-retest reliability (r = 0.84, p < 0.001) were good. The DACOBS-18 has satisfactory discriminative power, with 99.1% sensitivity and 74.3% specificity in discriminating low risk for psychosis from schizophrenia patients. The DACOBS-18 subscales correlate significantly with psychotic symptoms and psychotic-like experiences. After Bonferroni correction, significant correlations between Safety Behaviors and neuropsychological functioning were found. Conclusions: The DACOBS-18 is a reliable scale with satisfactory discriminative power and thus may be a valuable self-report screening tool for use in everyday dinical practice with psychotic patients and with people at risk for psychosis. Further research on its relationship to objective cognitive measures is needed. (C) 2017 Elsevier B.V. All rights reserved.