The dyskinesia Identification System Condensed User Scale (DISCUS): reliability, validity, and a total score cut-off for mentally ill and mentally retarded populations.

Items means and standard deviations, reliability, and validity for the Dyskinesia Identification System Condensed User Scale (DISCUS) are presented for mentally ill and mentally retarded populations. A total score cut-off was developed and tested against physician diagnosis and the Research Diagnoses for Tardive Dyskinesia (RD-TD; Schooler & Kane, 1982). DISCUS total score reliability was .92 for mentally ill and .91 for mentally retarded individuals. The DISCUS total score was significantly greater for 108 diagnosed tardive dyskinesia (TD) cases compared to 108 matched controls. The DISCUS total score of 5 or above was associated significantly with physician TD diagnosis and the RD-TD intensity criterion. The psychometrically derived DISCUS cut-off score of 5 or above is a "red flag" that clinicians may use in monitoring individuals prescribed antipsychotic medication for TD.