The Whitaker Index of Schizophrenic Thinking (WIST) and thirteen systems for diagnosing schizophrenia

Developed the present study in conjunction with a project that evaluated the psychiatric diagnosis of schizophrenia (Landmark, 1982; Landmark & Leslie, 1982). This design, which included 13 different interview systems for diagnosing schizophrenic disorders, allowed for an in-depth analysis of the Whitaker Index of Schizophrenic Thinking (WIST). Eighty-five outpatients who were receiving long-term chemotherapy for schizophrenia at the Moditen Clinic of London Psychiatric Hospital were reassessed individually using each of the 13 systems, following a clinical interview format, and the WIST. Major statistical analysis evaluated the concurrent validity and discriminatory efficiency of the WIST in comparison to the 13 systems. The WIST was found to show a consistently high agreement with each of the 13 systems for an average WIST discriminatory efficiency of 70%. The WIST is suggested as a practical, easily administered, diagnostic tool that performs well in comparison to the interview systems.