Functional impairment and the DSM-5 dimensional system for personality disorder.

The DSM-5 has included for further research a new dimensional measure of personality disorder, operationalized in the Personality Inventory for DSM-5 (PID5). It is important to investigate if extreme variants of these traits are associated with functional impairment, because functional impairment is a key aspect of the definition of personality disorder. The current study investigated this relationship in 989 college students and 91 clinical patients. The PID5 facets were meaningfully associated with measures of functional impairment in both samples, although the clinical sample evidenced more pathological levels of most traits, as might be expected. Overall, the PID5 appears to be a useful measure for the new DSM-5 system of personality disorder diagnosis.