A Multi-method Approach to Understanding the Role of Psychosocial Functioning in the Context of DSM-5 Personality Disorder Diagnosis

It is widely (although not universally) agreed that DSM personality disorder (PD) diagnosis should change from a categorical to a personality trait-based dimensional system, but extreme levels of pathological traits alone are thought to be insufficient to warrant a PD diagnosis (e.g., Livesley, 2003). Arguments for assessing functional difficulties in addition to maladaptive traits have contributed to the PD diagnostic model in DSM-5 Section III, which features two main diagnostic criteria: impaired personality functioning and pathological personality traits (American Psychiatric Association, 2013). Impaired personality functioning refers to fundamental disturbances in thinking about and experiencing oneself and others, as well as in the capacity for forming productive relationships with others and appropriate social roles. Personality functioning describes functional difficulties that are considered a fundamental component of PD pathology. However, the definition of personality functioning does not explicitly include the external consequences of psychopathology, such as poor job performance or multiple divorces, which usually fall into the category of functional difficulties. As an emerging model of psychopathology, Section III needs further research. To determine empirically what type of functional difficulties are associated with PD, comprehensive assessment of the domain of psychosocial functioning is necessary. Furthermore, PD diagnosis can be improved when we better understand the empirical overlap of personality traits, personality functioning, and their consequences. In a sample of 402 community adults and psychiatric outpatients, I examine relations among these three domains using a variety of self-report instruments and a semi-structured interview of functioning in various life domains. Although the constructs of traits, personality functioning, and functional consequences are conceptually distinct, results indicate the difficulty in making empirical distinctions in many cases, especially through self-report. Moderate to strong correlations found among these domains using self-report demonstrate the need for considering the empirical structure of the components of personality pathology rather than the rational separation of constructs. The use of a functioning interview provides a richer and more specific picture of daily life functioning than self-report, but it is not practical for assessing global functioning and may be better used clinically.