Measuring dysfunction as an essential component of the DSM-V personality disorder diagnosis: validation of the SIPP-118. Paper presented at the 12the ISSPD Congress, Melbourne, Australia.

Important in the DSM-V diagnosis of personality disorders (PDs) is the explicit evaluation of personality dysfunction, apart from the assessment of (extreme) traits (Clark, 2007). Therefore, more insight is required in the specific nature of dysfunction, and particularly, its distinction from personality traits. Accordingly, valid and reliable measures of dysfunction are needed.
The Severity Indices of Personality Problems (SIPP-118) is a possible dysfunction measure, created to assess core components of personality pathology, that are supposedly more changeable and responsive to psychotherapy than the more stable personality traits (Verheul et al., 2008). They reflect adaptive capacities that are generically impaired in PDs, and can be conceptually linked to personality (dys)functioning.
This study examines the validity of the SIPP-118 as a dysfunction measure in a sample of 150 Belgian psychiatric inpatients. Hierarchical regression analyses are used to determine the incremental validity of the SIPP-118 to predict DSM-IV PDs (as measured by the ADP-IV), beyond variance already accounted for by the NEO-PI-R traits. This would demonstrate to what extent the SIPP-118 specifically measures dysfunction, without being confounded by trait content. However, because it might still contain traits outside the FFM, the SIPP-118 is additionally validated against other indices of dysfunction (e.g. GAF-scores).