Comparative cognitive and psychomotor effects of single doses of Valeriana officianalis and triazolam in healthy volunteers

Hum Psychopharmacol. 2003 Dec;18(8):619-25. doi: 10.1002/hup.542.


Objectives: To assess the cognitive and psychomotor effects of single oral doses of valerian in healthy volunteers in comparison with a placebo and the hypnotic agent triazolam.

Methods: In a double-blind, placebo-controlled, four-way crossover study nine healthy subjects (5 males, 4 females) received in random order valerian 500 mg, valerian 1000 mg, triazolam 0.25 mg and placebo. Doses were separated by a wash-out period of at least 1 week. Subjects were tested before each dose and at 2, 4 and 8 h after the dose of each compound using the critical flicker fusion (CFF), choice reaction time (CRT), digit symbol substitution test (DSST), symbol search test (SST), digit span test (DST) and visual analogue scales of mood.

Results: Repeated measures ANOVA was used to examine the changes in performance on tests over time and significant effects were further analysed using simple main effects analysis with least significant difference corrections. Statistically significant differences were only noted for the cognitive tests: SST (F(3, 8)=3.182, p<0.05) and DSST (F(3, 8)=9.688, p<0.005). In both cases the differences between groups were due to the effects of triazolam.

Conclusion: These data confirm that at recommended therapeutic doses, triazolam has detrimental effects on cognitive processes in healthy volunteers as found in previous studies. Valerian was without effect on either cognitive or psychomotor performance in healthy volunteers at the doses used in this study. Should the hypnotic activity of valerian be confirmed in randomized double-blind trials it may be a less troublesome alternative to benzodiazepines in the treatment of insomnia.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Capsules
  • Choice Behavior / drug effects
  • Cognition / drug effects*
  • Cross-Over Studies
  • Dose-Response Relationship, Drug
  • Double-Blind Method
  • Female
  • Flicker Fusion / drug effects
  • Humans
  • Male
  • Plant Extracts / pharmacology
  • Plant Roots / chemistry
  • Psychomotor Performance / drug effects*
  • Reaction Time / drug effects
  • Triazolam / pharmacology*
  • Valerian / chemistry*


  • Capsules
  • Plant Extracts
  • Triazolam