On the discriminant validity of the Inventory of Interpersonal Problems (TIP): Interpersonal problems in patients with personality disorder

Background: Conceptionally a considerable overlap exists between the Inventory of Interpersonal Problems (TIP) and circumplex models of personality as well as diagnostic criteria of personality disorders (PD). Objective: (1) Do the TIP scales distinguish patients with PD from patients without any PD in a practically significant way? (2) Is the interpersonal circumplex suitable to discriminate specific types of PD from each other? Method: TIP data of n = 368 psychotherapy inpatients with PD and n = 368 patients without any PD from the same hospitals were analyzed. Results: Discriminant analysis between the two groups yielded one significant discriminant function, which showed a reclassification rate of 63%. Using ipsatized scores a decrease of 5% in reclassification was observed. Representations of seven types of PD in circumplex space showed statistically significant differences, most of which were in accordance with clinical conceptions and empirical findings. Conclusions: TIP scales performed moderately well in discriminating between patients with and without any PD. However, in accordance with theoretical assumptions several PD could be located in circumplex space, which supports further application of the TIP in the context of indication and evaluation of PD interventions.