MMPI Disability Profile Is Associated With Degree of Opioid Use in Chronic Work-related Musculoskeletal Disorders

Abstract

To examine the relationship between level of opioid use and Minnesota Multiphasic Personality Inventory (MMPI) findings among chronic pain patients who were about to begin a functional restoration program. A prospective cohort study of patients with chronic disabling occupational musculoskeletal disorders. A total of 768 consecutive patients with valid MMPI were divided into 2 groups: 398 patients who reported no opioid use upon admission (No); and 370 patients who reported opioid use upon admission (Yes). Average daily opioid doses (in morphine equivalents) could be determined for 287 of 370 patients, who were further divided into 4 opioid subgroups: Low (>0 to 30 mg, n=148); Medium (>30 to 60 mg, n=57); High (>60 to 120 mg, n=47); and Very High (>120 mg, n=35). Seventy-five percent of the patients who produced valid MMPI profiles could be classified into 1 of the 4 MMPI profiles. Of those patients who could be classified, approximately 7% showed a Normal profile, 15% showed a Conversion V, 9% showed a Neurotic Triad, and 69% showed the Disability Profile. Although the Disability Profile accounted for the majority of patients in all opioid subgroups, the proportions did increase with pretreatment opioid dose, as expected, indicating a relationship between degree of psychopathology and level of pretreatment opioid use. Patients who did not take pretreatment opioids showed the highest proportions of Conversion V and Normal profiles, which indicate a lesser degree or absence of psychopathology, respectively. Patients who took pretreatment opioids were more than one-and-a-half times as likely as patients who did not take pretreatment opioids to produce the Disability Profile, whereas patients taking very high doses of pretreatment opioids were nearly 3 times as likely to produce this profile as patients who took no pretreatment opioids. The results of this study support the hypothesis that increasing levels of pretreatment opioid use is associated with less desirable MMPI profiles, specifically the Disability Profile and, thus, greater levels of pretreatment psychopathology.