Sleep improving effects of a single dose administration of a valerian/hops fluid extract - a double blind, randomized, placebo-controlled sleep-EEG study in a parallel design using electrohypnograms.
Repetitive administrations of valerian/hops combinations have been widely used for self-administered therapy of sleep disturbances. This investigation focuses on the question if a single administration can be an effective sleep aid. Two parallel groups of n = 20 (verum) and n = 22 (placebo) were tested. Each subject spent two consecutive nights in the lab (reference night and medication night). Medication consisted in giving verum or placebo to poor sleepers identified by a validated sleep questionnaire (Schlaffragebogen SF-B). Two ml of the liquid ex?tract or similar smelling placebo were diluted in 50 ml water (flavoured with honey) and administered 15 minutes before EEG recording during the medication night. The data analysis is based on the electrohypnogram - a method derived from a validated computer assisted automatic analysis for depth of sleep. Differences between the reference nights and medication nights were evaluated and tested for significance. Time spent in sleep (values of the sleep frequency index "SFx" of the electrohypnogram of 74% or lower) was significantly higher for the verum group in comparison to the placebo group (p<0.01). The difference with respect to time spent in deeper sleep (i.e. 68% and lower or 62% and lower) between reference and medication night was also statistically significant at p<0.01. This parameter correlated with the difference in quality of sleep between the two consecutive nights as derived from the sleep inventory SF-A sub-score (subjects evaluation) with r = 0.48 at p<0.0001. The EEG derived parameter "sleep quantity" as calculated from the electrohypnogram proved superiority of the valerian/hops combination over placebo. Thus, the present investigation has shown evidence that a valerian/hops fluid extract can be used successfully using a single administration.