A carefully designed study assessed the short-term (single dose) and long-term (14 days with multiple dosage) effects of a valerian extract on both objective and subjective sleep parameters. The investigation was performed as a ran- domised, double-blind, placebo-controlled, cross-over study. Sixteen patients (4 male, 12 female) with previously estab- lished psychophysiological insomnia (ICSD-code 1.A.1.), and with a median age of 49 (range: 22 to 55), were included in the study. The main inclusion criteria were reported primary insomnia according to ICSD criteria, which was confirmed by polysomnographic recording, and the absence of acute dis- eases. During the study, the patients underwent 8 polysom- nographic recordings: i. e., 2 recordings (baseline and study night) at each time point at which the short and long-term effects of placebo and valerian were tested. The target vari- able of the study was sleep efficiency. Other parameters de- scribing objective sleep structure were the usual features of sleep-stage analysis, based on the rules of Rechtschaffen and Kales (1968), and the arousal index (scored according to ASDA criteria, 1992) as a sleep microstructure parameter. Subjective parameters such as sleep quality, morning feeling, daytime performance, subjectively perceived duration of sleep latency, and sleep period time were assessed by means of questionnaires. After a single dose of valerian, no effects on sleep structure and subjective sleep assessment were ob- served. After multiple-dose treatment, sleep efficiency showed a significant increase for both the placebo and the valerian condition in comparison with baseline polysomno- graphy. We confirmed significant differences between valer- ian and placebo for parameters describing slow-wave sleep. In comparison with the placebo, slow-wave sleep latency was reduced after administration of valerian (21.3 vs. 13.5 min respectively, p < 0.05). The SWS percentage of time in bed (TIB) was increased after long-term valerian treatment, in comparison to baseline (9.8 vs. 8.1 % respectively, p < 0.05). At the same time point, a tendency for shorter sub- jective sleep latency, as well as a higher correlation coeffi- cient between subjective and objective sleep latencies, were observed under valerian treatment. Other improvements in sleep structure ± such as an increase in REM percentage and a decrease in NREM1 percentage ± took place simultaneously under placebo and valerian treatment. A remarkable finding of the study was the extremely low number of adverse events during the valerian treatment periods (3 vs. 18 in the placebo period). In conclusion, treatment with a herbal ex- tract of radix valerianae demonstrated positive effects on sleep structure and sleep perception of insomnia patients, and can therefore be recommended for the treatment of pa- tients with mild psychophysiological insomnia. Introduction The prevalence of sleep disturbances is between 20 and 40 % of the population in the Western European countries; it increases with age. About 40 % of these patients use hypnotics occasion- ally, and 4 to 6% of the patients receive daily doses (Hajak and Rüther, 1995). The effect of hypnotics, however, is not stable: epidemiological investigations have shown that sleep distur- bances persist in 40 to 50 % of the treated patients (Holzrichter et al., 1994). The most widely used substances for the treatment of sleep disturbances are benzodiazepines and benzodiazepine recep- tor agonists, such as zopiclone and zolpideme. An advantage of these substances is their fast and reliable induction of sleep. However, they do not restore the normal sleep macrostructure: studies have determined reduced SWS sleep, often accompa- nied by REM sleep reduction, under treatment with benzodia- zepines (BorbØly, 1986). The chief disadvantages of benzodia- zepines are the appearance of hangover effects, drug tolerance, rebound insomnia after withdrawal, and the risk of addiction (Laux, 1995). Although benzodiazepine-receptor agonists have shorter half-lives than most benzodiazepines, similar side effects have likewise been observed in these substances (Noble et al., 1998). Long-term treatment of sleep disturbances with benzodiazepines and benzodiazepine receptor agonists is therefore inadvisable due to these side effects. Other drugs suitable for the treatment of sleep disorders are antidepressants, antihistamines, and low-potency neuroleptics with a sedative effect. Together with varying negative effects on the proportion of REM and NREM sleep stages, they may give rise to many typical side effects. The indications to administer these drugs are therefore mainly sleep disturbances accom- panied by corresponding psychiatric symptoms or parasomnia. Natural remedies prepared from plants ± such as extracts and teas from valerian, melissa, hops, and St. Johns wort ± are Critical Evaluation of the Effect of Valerian Extract on Sleep Structure and Sleep Quality F. Donath 1 , S. Quispe 1 , K. Diefenbach 1 , A. Maurer 1 , I. Fietze 2 , I. Roots 1 1 Institute of Clinical Pharmacology, CharitØ University Medical Center, Humboldt University of Berlin, Germany 2 Clinic of Internal Medicine I, CharitØ University Medical Center, Humboldt University of Berlin, Germany Pharmacopsychiatry 2000; 33: 47 ± 53  Georg Thieme Verlag Stuttgart · New York ISSN 0176-3679 nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn Original Paper nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn 47 Received: 20. 4. 1999 Revised version: 6. 7. 1999 Accepted: 21. 10. 1999 Downloaded by: University of Pittsburgh. Copyrighted material.