Personality disorders at the interface of psychiatry and the law: legal use and clinical classification

Personality disorders have a complex relationship with the law that in many ways reflects their complexity within the clinical and research communities. This paper addresses expert testimony about personality disorders, outlines how personality disorders are assessed in forensic cases, and describes how personality disorders are viewed in different legal contexts. Reasons are identified why personality disorders are not generally accepted as significant mental illness within the legal system, including high incidence of personality dysfunction in criminal populations, frequent comorbidity of personality disorders making it difficult to determine direct causation, and difficulty determining where on a continuum personality traits should be defined as illness (or not). In summary, the legal system, to a significant degree, mirrors the clinical conception of personality disorders as not severe mental diseases or defects, not likely to change, and most often, under volitional control.