Published online by Cambridge University Press: 22 July 2021
At the turn of the twenty-first century, our understanding of personality disorders radically evolved as research on their biological characteristics and effective evidence-based treatments (EBTs) emerged to challenge preexisting notions of these syndromes as defensive, psychologically determined, and untreatable. Reflecting the turmoil of a paradigm shift, intense controversy raged in attempts to revise the diagnostic system for personality disorders in the transition from the DSM-IV to the DSM-V. Proposed changes included both the elimination of five of the ten existing DSM personality disorders (narcissistic, histrionic, schizoid, paranoid, and dependent) and the implementation of a complex diagnostic system involving the evaluation of both categorical prototypes and dimensional traits of personality. The extremity of these proposed changes in the diagnostic system provoked major opposition among prominent experts, ultimately leading to the retention of the existing set of personality disorder criteria and relegation of the proposed alternative model to a section calling for further research. One prominent change in the transition to the fifth edition of DSM was the elimination of the multi-axial system, ending the segregation of Axis II disorders from Axis I disorders.