A Critical Review of Rating Scales in the Assessment of Movement Disorders in Schizophrenia

Tardive dyskinesia (TD) has been recognised for nearly 50 years. It is associated with antipsychotic drugs and is usually persistent with no satisfactory treatment. It is believed to be under-documented in medical records. Many rating scales have been devised to measure TD. Studies have demonstrated variability between the rating scales on the measures of reliability and validity, the clinical setting used, the raters involved in the ratings and the provision of definitions and instructions. Scales that include too many items to be comprehensive become cumbersome and difficult to use. A compromise is to reduce the number of items and have add-in items for individual patients. A good example of this approach is the Abbreviated Dyskinesia Scale (ADS). Rating scales continue to be the best available methods to evaluate dyskinesia but in view of the shortcomings of validity, reliability and utility for clinical use, more efforts need to be done to improve current rating scales and to develop new ones.