A randomized, placebo-controlled clinical trial on the efficacy of chiropractic therapy on premenstrual syndrome

Abstract

Objective: To evaluate the efficacy of chiropractic therapy on the treatment of symptoms associated with premenstrual syndrome. Design: A prospective, randomized, placebo-controlled, crossover clinical trial. Setting: Multicenter private clinics. Subjects: Twenty-five subjects with diagnosed premenstrual syndrome (with a Moos premenstrual syndrome questionnaire plus daily symptom monitoring). Intervention: After randomization, 16 of the subjects received high-velocity, low-amplitude spinal manipulation plus soft tissue therapy 2 to 3 times in the week before menses for at least 3 cycles. The remaining 9 subjects received a placebo treatment with a spring-loaded adjusting instrument wound down for minimum force. After a 1-cycle washout, the 2 groups changed over. Outcome Measure: Daily rating of symptom level, comparing total scores for premenstrual week with baseline for treatment and placebo phases. Data Analysis: The data were analyzed with paired Student t tests and Wilcoxon signed rank tests, with the statistical signifi-cance set at P < .05. Results: There was a significant decrease in scores after treatment compared with baseline scores ( P = .00001) and a statistically significant decrease in scores for the treatment phase compared with the placebo ( P = .006). For group 1 (n = 16), there was a significant decrease in scores after treatment compared with baseline scores ( P = .0001) and a statistically significant decrease in scores for the treatment phase compared with the placebo ( P = .041). For group 2 (n = 9), there was a significant decrease in scores during treatment compared with the baseline ( P = .01); however, there was no difference at the P = .05 level between treatment and placebo scores. Conclusions: Within the limitations of the study, the results support the hypothesis that the symptoms associated with PMS can generally be reduced by chiropractic treatment consisting of adjustments and soft-tissue therapy. However, the role of a placebo effect needs further elucidation, given that the group receiving the placebo first, although improving over the baseline, showed no further improvement when they had actual treatment. (J Manipulative Physiol Ther 1999;22:582–5)