Many women with menopause-related symptoms will seek CAM remedies. (34
) Common reasons for choosing a CAM therapy include concerns about drug toxicity and side effects, cultural attitudes, and the stigma of having a mental disorder. In addition, many women do not seek conventional therapies for menopausal symptoms because they do not view their symptoms as resulting from a medical condition. Women seeking CAM remedies for menopause often come from vulnerable populations such as the uninsured or racial and ethnic minorities. (34
) Therefore, the testing of CAM products for menopause-related anxiety is needed to identify effective remedies. Early phase II trials, like the current study, can inform the design of future trials so that their results are likely to be clinically meaningful. In this regard, the negative findings of the current study should be interpreted cautiously due to the limited sample size and possibility of a type 2 error in our results.
A substantial number of studies suggest that black cohosh may be effective in reducing the vasomotor symptoms of menopause (18
), although this has not been a universal finding. (21
) Fewer studies, however, have examined the psychological benefits of black cohosh. One double-blind, placebo-controlled comparison of black cohosh versus HRT for vasomotor symptoms found a benefit of black cohosh (versus placebo and HRT) for psychological symptoms. (38
) However, this study was criticized because HRT was not superior to placebo in reducing vasomotor symptoms. (39
) Another study comparing two dose levels of black cohosh for vasomotor symptoms in 150 menopausal women found that both doses improved mood ratings from ‘mild’ to ‘normal’.
More recently, Nappi et al. (19
) compared the efficacy of black cohosh versus HRT in reducing menopausal symptoms in 64 women and found a significantly anxiolytic (p<0.001) and antidepressant (p< 0.001) benefit for black cohosh that was similar to HRT. Similarly, Osmers et al. (40
) found a significant reduction in menopause-related psychological symptoms with black cohosh (versus placebo) (p=0.019), while Briese et al. (20
) found a greater reduction in the psychological symptoms during combined black cohosh plus hypericum therapy versus black cohosh monotherapy. Finally, Oktem al. (41
) compared fluoxetine to black cohosh in 120 climacteric women and found black cohosh to be superior to fluoxetine in reducing vasomotor symptoms, and fluoxetine superior to black cohosh in reducing depressive symptoms.
There are several caveats that need to be considered in interpreting the current findings. A lower than expected subject enrollment led to a smaller than expected sample size with limited power to detect differences between treatment conditions. We note that the current trial was designed as a preliminary study supported by a limited exploratory grant. The study was originally powered to detect only relatively large differences in the primary outcome measure. Larger sample sizes would have been required to detect smaller, clinically meaningful, differences in the secondary outcome measures (if they actually exist). Thus, it is possible that the negative findings are an artifact, or type 2 statistical error, resulting from the small sample size. It is also possible that black cohosh produces no clinically meaningful anxiolytic effect in menopausal women.
It is possible that the black cohosh extract preparation and dosage used in this study may have influenced the current results. In this regard, the majority of controlled clinical trials employed a proprietary brand of black cohosh extract (i.e., Remifemin®). The UIC black cohosh material may have possessed less anxiolytic activity than other black cohosh extract preparations used in other studies. It is also possible that a larger dose of the UIC material may have been necessary to demonstrate anxiolytic activity. The selection of the black cohosh dosage was based upon earlier UIC black cohosh trials. The use of another black cohosh material standardized to different pharmacologically ‘active’ constituents may have produced different results. Finally, it is possible that black cohosh material used had little or no vasomotor or anxiolytic activity and that the current results merely represent a regression toward the mean.