This study evaluated the psychometric properties and factor structure of the Calgary Depression Scale for Schizophrenia (CDSS) across different levels of the schizotypy continuum. A combined sample of high-schizotypy, at-risk mental states, and patients with first-episode psychosis was assessed for depression and other clinical and functional outcomes. Additionally, experience sampling methodology was used to assess depressive and psychotic-like experiences in daily life. The CDSS exhibited solid internal consistency, validity, and discrimination between depressed and nondepressed participants. Confirmatory factor analyses and the associations of the resulting factors with clinical and functional measures supported a two-factor structure that included general depression and guilt factors. Furthermore, both factors of the CDSS were differentially related to positive and negative symptoms of psychosis in daily life. The CDSS appears to have two underlying psychopathological dimensions and to be a reliable and valid measure for assessing depression across the schizotypy continuum.
Keywords: Calgary depression scale for schizophrenia; depression; experience sampling; factor analysis; psychosis; schizotypy.