The convergence and predictive validity of the Multidimensional Pain Inventory and the Personality Assessment Inventory among individuals with chronic pain.

Objective: To explore the convergence, redundancy, and validity of the Multidimensional Pain Inventory (MPI) and the Personality Assessment Inventory (PAI) in a chronic pain treatment setting. Participants: Data from intake (N=235) and follow-up (N=187) for individuals with an average of 9 years of chronic pain who participated in a 20-day integrative treatment program were analyzed. Outcome Measures: Oswestry Disability Index, Beck Depression and Anxiety inventories, Rand Short-Form Health Survey, and clinician-rated ability to stand and carry. Results: Conjoint factor analyses suggested that the MPI and PAI combine to tap five orthogonal factors: Negative Affect, Support, Externalizing, Physical Dysfunction, and Impulsivity. MPI and PAI scales significantly related to various aspects of client functioning, although these scales were more limited in predicting clinician-rated markers and change during treatment. Conclusion: Results support the combined use of the MPI and PAI to understand patient heterogeneity and predict treatment outcome in chronic pain samples. (PsycINFO Database Record (c) 2010 APA, all rights reserved)