The Rorschach Schizophrenia Index (SCZI): an examination of reliability, validity, and diagnostic efficiency

In this study, we investigate the reliability, validity, and diagnostic efficiency of the Rorschach Schizophrenia Index (SCZI) in relation to the accurate identification of patients diagnosed with Diagnostic and Statistical Manual of Mental Disorders (4th ed. [DSM-IV], American Psychiatric Association, 1994) schizophrenia or other psychotic disorder (PD) according to the methodological recommendations offered by Wood, Nezworski, and Stejskal (1996). Seventy-eight patients who were found to meet DSM-IV criteria for a PD or Axis II disorder (PD = 33; borderline personality disorder = 23; Cluster A personality disorders = 9; Cluster C personality disorders = 13) and 50 nonclinical participants were compared on the SCZI. The results of this study indicate that the SCZI is internally consistent and can be reliably scored. In addition, the SCZI was used effectively in differentiating PD patients from patients with an Axis II disorder and from the participants in the nonclinical sample. Also, the SCZI variable was found to be empirically related to the presence of a DSM-IV diagnosis of PD. Finally, this variable could be employed for classification purposes in ways that were clinically meaningful in the diagnosis of a PD. Conceptual and methodological issues are discussed in relation to the assessment of psychosis.