Objective: The aim of this study was to review and discuss the evidence for dimensional classification of personality disorders and the historical and sociological bases of psychiatric nosology and research.
Method: Categorical and dimensional conceptualisations of personality disorder are reviewed, with a focus on the Diagnostic and Statistical Manual of Mental Disorders-system's categorisation and the Five-Factor Model of personality. This frames the events leading up to the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition, personality disorder debacle, where the implementation of a hybrid model was blocked in a last-minute intervention by the American Psychiatric Association Board of Trustees. Explanations for these events are discussed, including the existence of invisible colleges of researchers and the fear of risking a 'scientific revolution' in psychiatry.
Results: A failure to recognise extra-scientific factors at work in classification of mental illness can have a profound and long-lasting influence on psychiatric nosology. In the end it was not scientific factors that led to the failure of the hybrid model of personality disorders, but opposing forces within the mental health community in general and the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition, Task Force in particular.
Conclusion: Substantial evidence has accrued over the past decades in support of a dimensional model of personality disorders. The events surrounding the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition, Personality and Personality Disorders Work Group show the difficulties in reconciling two different worldviews with a hybrid model. They also indicate the future of a psychiatric nosology that will be increasingly concerned with dimensional classification of mental illness. As such, the road is paved for more substantial changes to personality disorder classification in the International Classification of Diseases, 11th Revision, in 2017.
Keywords: Diagnosis; history of psychiatry; methodology; personality disorders; philosophy of science.
© The Royal Australian and New Zealand College of Psychiatrists 2015.