This study tested the effects of valerian on sleep in older women with insomnia in a manner consistent with typical self-administration of valerian in the U.S. Both after a single dose and two-week nightly dosing of valerian, none of the self-report, PSG, or actigraphic sleep outcomes showed improvement of sleep compared to placebo. Self-reported sleep latency in the home sleep logs improved equally with both treatments indicating a placebo effect, but this also could reflect a regression to the mean. Compared to baseline PSG, greater nocturnal wakefulness was observed after two weeks of valerian than was observed after two weeks of placebo. One case in the literature has reported stimulation, not sedation, with valerian (43
), and this is recognized by herbalists as a potential paradoxical effect of valerian (44
Previous studies of valerian have been generally inconclusive. Although participants reported improved sleep with valerian in two studies of older persons, one study did not use statistical tests to compare the valerian and placebo groups (27
), and the other study tested the proportion reporting improvement rather than actual ratings of sleep quantity and quality (28
). Two studies of older persons reported no significant differences in self-report or PSG sleep outcomes (29
). A recent RCT in persons with arthritis using a higher dose (600 mg) of the same valerian preparation used in this trial also reported no significant improvements in either self-report or actigraphic sleep outcomes, but PSG outcomes were not assessed (45
The current study was initiated before recent evidence has emerged that shows valerian is a less promising therapy than suggested by earlier research. The most recent studies with rigorous designs reported no significant benefits on sleep outcomes from valerian treatment (46
) and a similar conclusion was made by an expert panel at the recent National Institutes of Health State of the Science Conference on insomnia (51
). In addition, a recent systematic review both of the English and German literature conducted by several authors of the current study concluded that the body of evidence on valerian and valerian combination preparations does not support the efficacy of the herb as a sleep aid (52
). However, a recent meta-analysis found improved self-reported sleep quality as a dichotomous (improved versus not improved) variable with valerian compared to placebo (53
). This review also reported inconsistent effects of valerian on self-reported sleep latency and PSG sleep outcomes, consistent with the other studies. Although some of the reviewed studies reported improvement with valerian administration over time (27
), few studies found significant improvement in any of the sleep outcomes when valerian was compared to placebo. Despite evidence from in vitro
studies of valerian effects on neuropeptide systems involved in sleep mechanisms (22
), dried valerian extract has not shown clinical efficacy as a sleep aid.
In the current sample, some inconsistencies between the self-report, PSG and actigraphy sleep outcomes were noted. Compared to self-report outcomes in the laboratory, self-reports in the daily logs showed longer sleep latencies, greater amounts of nocturnal wakefulness, and lower sleep efficiencies, but curiously similar overall sleep quality. Sleep logs and actigraphic measures at home showed similar amounts of nocturnal wakefulness (~40-60 min) and sleep efficiency (~85%). However, an opposite pattern was observed in the laboratory. PSG-derived WASO was increased and SE was reduced, compared to self-report outcomes both in the laboratory and at home and to actigraphy at home. The discrepancy between actigraphy and PSG may be related to an underestimation of wakefulness by actigraphy (41
). The discrepancy between self-report and PSG may represent some degree of acclimation to disrupted sleep among the older women. Previous studies have reported similar findings indicating that some older women underestimate the severity of their sleep disturbances as recorded by PSG (3
). In a previous study, Vitiello and colleagues reported moderately disrupted sleep on PSG recordings in older healthy women who did not complain of sleep problems, but this pattern was not observed in healthy older men (3
). More research is needed to explore moderators between objective measures and perceptions of sleep, especially in older women and men.
On all three types of sleep measures (self-report, PSG, and actigraphy), women showed more problems with sleep maintenance than sleep onset. These observations are consistent with findings from a recent meta-analysis that showed greater problems with sleep maintenance with aging (4
). Valerian may not be a good choice for treating sleep maintenance insomnia given findings from a recent pharmacokinetic study that showed valerenic acid (a pharmacologically active marker compound for valerian) was increased in serum within an hour, and no detectable levels were observed four hours after administration (56
). This pharmacokinetic pattern avoids residual sedation in the morning, and suggests that, if valerian was beneficial as a sleep aid, effects would most likely facilitate sleep onset. However, the results from our recent extensive review of the literature did not find evidence to support the efficacy of valerian to treat sleep onset insomnia. Our observation of increased nocturnal wakefulness on PSG after two weeks of valerian provides evidence that valerian has the potential to increase problems with sleep maintenance in older women.
We had hoped that the results of this phase 2 clinical trial would provide preliminary data from a well-defined sample of older women with insomnia for a larger study of valerian effects on sleep. Had valerian shown similar improvement in sleep as had been reported in a previous clinical trial comparing a hypnotic to placebo in older adults with insomnia (57
) a sample size of 15 would have provided 81% power to detect a 10% increase in self-reported sleep efficiency (95% confidence interval 3.68-16.32) and a 7% increase in PSG sleep efficiency (95% confidence interval 2.17-11.83). Although the findings from this study are limited by the stringent eligibility criteria and small sample size, the lack
of a valerian effect to improve sleep outcomes was clear; a finding consistent with evidence from several other recently published rigorous trials of valerian. Any future research on valerian could be focused on the potential efficacy of different valerian preparation types, such as tinctures, rather than the typical testing of over-the-counter products. Future research on herbal therapies for insomnia could also report, and possibly limit the sample to specific types of insomnia symptoms (e.g., sleep onset problems versus sleep maintenance problems). Such specificity would clarify whether or not a product is differentially efficacious depending on the symptom pattern.
In summary, a phase 2 randomized crossover trial both of one day and two-week nightly valerian treatment did not improve self-reports, PSG, or actigraphic sleep outcomes in older women with insomnia. No improvement occurred in PSG sleep outcomes with either valerian or placebo; conversely, nocturnal wakefulness increased more with valerian. Thus, we do not recommend use of valerian for sleep disturbance in older women with insomnia.