Screening for personality disorders in a nonclinical population.

Based on the Inventory of Interpersonal Problems (IIP), the IIP-PD and the IIP-C screening scales were developed to distinguish personality disorder (PD) from non-PD and Cluster C from other PD, respectively, in a clinic population. Two studies were conducted to determine (a) validity and reliability of these IIP scales for PD screening in a nonclinical population, (b) specificity of IIP-C for identifying Cluster C, and (c) usefulness of the IIP scales for screening Cluster A. College students were screened using the IIP scales (Study 1, N = 454, Study 2, N = 87). High and low scorers completed PD-related questionnaires in Study 1 and a clinical interview for PD symptomatology in Study 2. Results indicated strong test-retest reliability, internal consistency, and factorial, convergent, and external validity. The scales tapped a common deficit in interpersonal relatedness, with some distinction between externalizing and internalizing dimensions, respectively, and both scales were positively and significantly associated with schizotypal traits. In conclusion, the IIP-PD and IIP-C are useful and valid screening instruments for identifying any versus no PD in nonclinical populations.