The effect of stress, anxiety and anxiolytic drugs on cognitive performance and decision making among healthy adults
Unlike the anxiolytic group of benzodiazepines which, as GABA-agonists, impair cognitive performance; Hypericum perforatum, considered an antidepressant and anti-anxiety herbal compound, affects multiple neurotransmitters in a non-competitive synergistic manner and may have nootropic potential. In a pre-clinical meta-analysis, we found it improved working memory and other cognitive facets in both stressed and non-stressed rodents, though the effect on the latter group was smaller. We conducted a randomized double-blind clinical trial: 81 healthy adults participants (aged 19 to 35, 41% females) attended two counter-balanced sessions: with 250 or 500 mg single dose of Remotiv (drug including H. perforatum extract), and with placebo. In both session, following a baseline psychological battery measuring mainly stress and anxiety, participants were administered with either H. perforatum or placebo). Sixty minutes later they underwent a computerized cognitive battery measuring mainly working memory and attention. Results show better recalling performance, for 250 mg Remotiv (vs. placebo) in the digit span and operation span tasks and less omission rates in a go / no-go task. However, the 500 mg Remotiv slightly impaired performance in these tasks. The anxiolytic effect of H. perforatum was minimal, and no interaction between stress or anxiety and the drug on cognitive performance was found. Regarding healthy adults, a single small dosage H. perforatum seems to have some benefit regarding several cognitive domains, regardless of the presence of anxiety or stress levels. However, the limited acute anxiolytic effect, does not allow H. perforatum to substitute benzodiazepines as a non cognitive-impairing acute anxiolytic agent.