The frequent finding that meeting criteria for one type of personality disorder (PD) is commonly associated with meeting criteria for several other PDs indicates significant problems in defining and measuring PDs independently of each other, whether measured categorically or dimensionally. This study was designed to enrich recent DSM descriptor sets and, with the enriched set of descriptors, develop refined PD dimensions. A large sample of patients with a PD or significant personality disturbance were studied, with most analyses based on self-report (SR) data, but with corroborative witness (CW) data also collected to validate refinement analyses. The original descriptor set comprised 139 DSM descriptors and 127 items obtained from other sources. Personality disorder dimensions of interest were refined by factor analyses. We specifically identify items that failed to "belong" to their original PD "base." A refined set of 92 items demonstrated greater independence of the underlying dimensions and suggested an underlying five-factor structure at some variance to the current DSM-IV cluster set. The study should assist measurement of individual PDs by identifying items and constructs that build to more homogeneous dimensions that define lower-order and higher-order PD traits.