The rating of psychiatric impairment in forensic practice: a review

One of the questions often asked of the psychiatric expert witness is to rate the extent of psychiatric impairment as part of the evaluation of a plaintiff in personal injury litigation, or of a claimant for statutory benefits. At present, there is no generally agreed upon or validated scale for the rating of psychiatric impairment, and the guides to the rating of permanent impairment which are available have not been adequately researched. This article reviews the few rating scales which have been published. It is concluded that, because of the increasing need for objective and valid rating of psychiatric impairment for legal and administrative purposes, there is an urgent need for research to determine the reliability and validity of psychiatric impairment rating scales. Nevertheless, the rating scales currently available do provide a structured approach to the rating of psychiatric impairment and offer a degree of objectivity, and therefore they should be utilized more frequently as clinical judgment within the often adversary setting of forensic practice may be influenced by non-clinical factors which may undermine the validity of the assessment.