Validity of the Somatic Complaints Scales of the MMPI‑2‑RF in an Outpatient Chronic Pain Clinic

Abstract

Chronic pain has become a significant medical issue. The Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF) is a broadband psychological test that has been validated for use across various medical settings and can aid in the assessment and treatment planning of chronic pain. In the current investigation, it was hypothesized that the somatic complaints scales of the MMPI-2-RF would demonstrate good convergent validity from a structured psychodiagnostic interview and other measures of pain and somatization, and lack gender bias. Patients (n = 200) who produced valid MMPI-2-RFs in an outpatient chronic pain clinic were included in the study. Patients were also administered the Modified Somatic Perception Questionnaire (MSPQ), Pain Disability Index (PDI), and the Structured Clinical Interview for DSM-IVTR (SCID). Zero-order and partial correlations (controlling for gender) were calculated between MMPI-2-RF scale scores and other criteria. Stepdown hierarchical regression analyses were used to detect bias. By and large, higher scale scores on the somatic/cognitive scales of the MMPI-2-RF were modestly or substantially correlated with MSPQ scores, PDI scores, and SCID Somatization symptom count, even after controlling for gender. Regression analyses suggested that the MMPI- 2-RF scale scores were not biased as a function of gender. These findings support the validity of specific MMPI-2-RF scales to help identify somatization and psychosocial functioning among patients with chronic pain. Identification of somatization early within the course of treatment of chronic pain may help focus treatment targets, including referrals for psychological interventions such as cognitive behavior therapy for chronic pain.