A revised taxonomy of patients with chronic pain.

OBJECTIVE To examine the taxonomic categories derived from a reorganization of the popular and useful Multidimensional Pain Inventory (MPI)/Multiaxial Assessment of Pain (MAP) system. DESIGN Cluster-analytic procedures were utilized to analyze data from 976 pain patients who presented for treatment at a pain clinic. Ward's method was utilized followed by seeded and unseeded k-means procedures and a discriminant function analysis. RESULTS Three clusters were interpreted as: Interpersonally Focused, Stoic, and Adaptively Focused. Discriminant analyses followed by internal and external classification analyses provide evidence for the stability and replicability of the new clusters. Fisher's linear discriminant classification function coefficients were produced for clinical use. CONCLUSIONS Meaningful differences exist between the new MPI clusters and those previously reported. The results provide a contribution toward improvements on the original and popular MPI/MAP system.