The Iowa Personality Disorder Screen (IPDS) was developed by Langbehn et al (1999) to serve as a brief interview-based measure, taking around 5 min to complete. It is an 11-item screening instrument used to evaluate whether a PD is present or absent in the psychiatric outpatient clinic setting (Langbehn et al., 1999). Most of the 11 items have follow up questions making up a total 19 possible questions. It can easily be integrated into standard diagnostic clinical interviews and initial validation research suggests that it is adequate in identifying patients requiring further evaluation to determine if they meet criteria for a personality disorder. Furthermore, a study by Trull and Armdur (2001) examined the effectiveness of the IPDS in a non-clinical sample of 103 undergraduate students and determined that it may be useful as a screening measure for PD in both clinical and nonclinical populations.
Retrospective analyses using 1,203 Structured Interview for Disorders of Personality-Revised (SIDP-R; Pfohl, Blum, Zimmerman,1995) interviews suggested that the IPDS items should provide good sensitivity and specificity (Langbehn et al., 1999). Furthermore, results from a prospective validation study, using a mixed group of 52 nonpsychotic inpatients and outpatients who were diagnosed showed that blind administration of the IPDS yielded excellent sensitivity (92%) and good specificity (79%). The IPDS shows promise as a quick PD screen for use in research settings or standard clinical interviews. Moreover, socio-demographic and psychopathological factors have been suggested to have little effect on the IPDS as screening instrument (Olssøn, Sørebø, & Dahl, 2011).
In a study by Morse and Pilkonis (2007) psychiatric and non-psychiatric samples were employed to compare the validity of three screening measures: the PD scales from the Inventory of Interpersonal Problems, a self-report version of the Iowa Personality Disorder Screen, and the self-directedness scale of the Temperament and Character Inventory. The screeners were highly correlated in a range from .71 to .77, despite their different theoretical origins. These findings suggest that the use of multiple screeners was not a significant improvement over any individual screener, and no single screener stood out as clearly superior to the others.
When using self-rating scales, clinicians should be mindful as individuals with PD see themselves in distorted ways and may not be able to give accurate accounts of their presenting difficulties (Klonsky, Oltmanns, & Turkheimer, 2002). Reports of symptoms have been shown to differ from those of their friends and families (Klonsky, Oltmanns, & Turkheimer, 2002), therefore interviews with people who know the patient well can improve the accuracy of a diagnosis.
This tool is not meant to be used as a diagnostic tool. Only a trained professional can properly diagnose a personality disorder. The formal diagnosis for a PD is ultimately a clinical decision that should be made by incorporating multiple sources and the screening measures are intended to aid clinicians in making decisions regarding identification of patients who are in need of a more thorough evaluation, but a formal diagnosis should not be given based exclusively on these data alone.
Olssen, I., Sørebø, Ø., & Dahl, A. A. (2011). A cross-sectional testing of The Iowa Personality Disorder Screen in a psychiatric outpatient setting. BMC Psychiatry, 11, 105. http://doi.org/10.1186/1471-244X-11-105
Siefert, C. J. (2010). Screening for Personality Disorders in Psychiatric Settings: Four Recently Developed Screening Measures, in Baer, L., Blais, M.A. (2010). Handbook of Clinical Rating Scales and Assessment in Psychiatry and Mental Health. N.Y: Human Press.
Trull, T.J. & Amdur, M. (2001). Diagnostic Efficiency of the Iowa Personality Disorder Screen Items in a Nonclinical Sample. Journal of Personality Disorders: Vol. 15, No. 4, pp. 351-357. https://doi.org/10.1521/pedi.15.4.351.19184