A critique of the proposed prototype rating system for personality disorders in DSM-5

The DSM-5 Personality and Personality Disorders (PDs) Work Group has recommended a reformulation of the PD section, one component of which is a replacement of specified operational criteria with a prototype matching dimensional rating system. The Work Group indicated that prototype ratings have been demonstrated to have good interrater reliability. No study was cited to support this statement, and a review of the reliability literature does not support this claim. The one study that directly compared the reliability of prototype and DSM-IV criteria counting approaches found the DSM-IV approach was much more reliably applied. The Work Group cited 2 studies supporting the validity of the prototype matching approach, one of which had significant methodological limitations and the other changed the a priori threshold on the PD prototype dimensional rating scale to categorize patients into PD positive and negative groups. The Work Group also cited 2 studies suggesting that prototype matching approaches are preferred by clinicians. Several studies have raised concerns about the adequacy of psychiatric diagnostic evaluations conducted in routine clinical practice thereby raising questions about the value of studies of clinicians' preferences in comparing different diagnostic practices. In conclusion, if the prototype matching dimensional approach described in the DSM-5 draft proposal is adopted, then it will have been adopted with essentially no empirical support demonstrating improved reliability or validity. In fact, there is evidence that reliability will be worse than the DSM-IV approach.