Background: Interest in alternatives to hormone therapy (HT) for menopausal symptoms increased following its association with serious health risks. In terms of phytotherapeutic interventions, while traditional use supports a range of herbs for treating menopausal symptoms, evidence from rigorous scientific trials is limited, and has largely focused on the phytoestrogenic plants. Because of some safety concerns over long-term use of isoflavones, the present study focused on two non-estrogenic herbs, Hypericum perforatum and Vitex agnus-castus, also employed in this context in the Anglo-American and European traditions. Both herbs have shown effectiveness for the alleviation of symptoms of premenstrual syndrome (PMS), which is reported to be more severe during the perimenopause, and may account for many of the so-called 'menopausal symptoms' at this time. Research on menopausal vasomotor symptoms is prone to substantial placebo responses. There has been much interest in increasing our understanding of the placebo response with a view to controlling it in clinical research and harnessing it in clinical practice. Methods & Results: A double-blind, randomised controlled trial (RCT), with a 16-week treatment phase, was conducted on 100 late-perimenopause and early postmenopause women. The herbal combination (Hypericum and Vitex) was not found to be superior to placebo for any of the endpoints - daily weighted flushing scores, overall menopausal symptoms (on the Greene Climacteric Scale) and depression (on the Hamilton Depression Inventory). However, significant improvements across the treatment phase were observed in both arms for all of these outcome measures. No significant change was found for either group on the Utian quality of life scale. The effects of the herbal combination were also examined on PMS-like symptoms in the small sub-population of late-perimenopausal women, and found to be superior to placebo for total PMS-like symptoms and the sub-clusters, PMS-D (depression) and PMS-C (cravings). The active treatment group also showed significant improvements on PMS-A (anxiety) and PMS-H (hydration), although these effects were not superior to placebo. Predictors of the placebo response were investigated and found to include study-entry anxiety for the outcome measures of flushing, depression and overall menopausal symptoms, and improvement during non-treatment run-in for depression and overall symptoms. Because no difference had been found between 'active' and placebo groups in the menopause RCT, it was hypothesised that the same predictors would predict the response to the study treatment. However, low anxiety was significantly associated with improvement in this group. None of the other variables that predicted the placebo response was relevant to the study treatment response. This finding is discussed with reference to the possibility that 'drug' effects and placebo effects are not necessarily additive, and that the same magnitude of effect in both arms might not necessarily imply activity via the same pathways. Conclusions: This research contributes to the growing body of scientific knowledge about evidence-based complementary therapies that informs the community, health-care providers and regulatory authorities. The findings may facilitate identification of potential placebo responders in future research. The need for more research in the area of mechanisms of placebo versus active responses is supported.
| Identifer | oai:union.ndltd.org:ADTP/232994 |
| Date | January 2009 |
| Creators | van Die, Margaret Diana, diana.vandie@rmit.edu.au |
| Publisher | RMIT University. Health Sciences |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | http://www.rmit.edu.au/help/disclaimer, Copyright Margaret Diana van Die |
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