Influence of psychological factors on the response to clomipramine in hospitalized chronic low back pain patients. Preliminary data from a psychometric study.

BACKGROUND: Chronic low back pain is a complex condition produced by multiple factors. Psychological disturbances have been found in previous studies using a variety of psychological tests. The most widely used self-administered questionnaire was the Minnesota Multiphasic Personality Inventory (MMPI). OBJECTIVE: To assess the response to clomipramine in chronic low back pain patients according to baseline MMPI scores. PATIENTS AND METHODS: Thirty chronic low back pain patients were given clomipramine intravenously during a ten-day hospital stay, then orally for 20 days. The dose was gradually brought up to 150 mg/d. The MMPI was administered on the day before treatment initiation. MMPI scores were not looked at until the end of the study. The Saint Antoine Questionnaire, a visual analog scale for pain, Schöber's maneuver, and the global result as assessed by the patients (success or failure) were evaluated on days 0 (D0), 4 (D4), 10 (D10), and 30 (D30). RESULTS: The initial mean MMPI scores for hypochondria, depression, and hysteria were significantly lower in the 23 patients (76%) who considered their treatment successful on D30. Among the 13 patients with high hypochondria and hysteria scores, five improved during hospitalization then had a relapse after returning home. CONCLUSION: The response to treatment with clomipramine was better in nondepressive patients. The hypochondria and hysteria scores were the best predictors of the response to clomipramine. These results may provide a basis for selecting those chronic low back pain patients most likely to benefit from clomipramine therapy.