Establishing a clinically relevant cutoff to the Dependency Scale from the dimensional clinical personality inventory

The Clinical Dimensional Personality Inventory (IDCP) is a 163-item self-report tool developed for the assessment of 12 dimensions of personality pathology. One of the scales comprising the instrument-the Dependency scale-is intended to provide psychometric information on traits closely related to the Dependent Personality Disorder (DPD). In the present study, we used both Item Response Theory modeling and Receiver Operating Characteristic curve analysis to establishing a clinically meaningful cutoff for the IDCP Dependency Scale. Participants were 2.481 adults, comprised by outpatients diagnosed with DPD, outpatients diagnosed with other PDs, and adults from the general population. The Wright's item map graphing technique revealed that outpatients were located at the very high levels in the latent scale continuum of the Dependency Scale, with a very large effect size for the mean difference between patients and non-patients. The ROC curve analysis supported a cutoff at 2.3 points in the Dependency Scale, which yielded 0.86 of sensitivity and 0.79 of specificity. Findings from the present investigation suggest the IDCP Dependency Scale is useful as a screening tool of the core features of the DPD. We address potential clinical applications for the instrument, and discuss limitations from the present study.