The Iowa Personality Disorder Screen: A validation study in a psychiatric population that receives long-term group psychotherapy for personality related problems.

Personality disorder (PD) is common among psychiatric patients, and diagnosing such disorders is of great importance for the choice of treatment. Diagnosing PD is a demanding and time-consuming process. The utilities of several PD screening instruments have been studied in different populations, but not in a population who receives long-term group psychotherapy. In the current study, we investigate the predictive properties of the Iowa Personality Disorder Screen (IPDS) in a sample of 694 psychiatric outpatients with and without PD who were admitted for psychodynamic long-term group therapy from 2012 to 2014. The definitive, reference diagnoses were defined according to the SCID-II, by which 484 patients (68%) warranted a PD diagnosis. The IPDS correctly classified 67.4 percent of all participants. Sensitivity (0.75) and specificity (0.51) were lower than in previous validation studies of IPDS. We discuss possible explanations related to the general concept of PD and, more specifically, to our study sample. Because of the weaker predictive properties of IPDS, we advise caution in use of the IPDS in similar clinical settings. Copyright © 2018 John Wiley & Sons, Ltd.