Lavender is one of few essential oils used in aromatherapy with evidence for general anxiety reducing effects, alongside rose oil having some evidence.[35] In animals exposed to the aroma of lavender (Lavandula officinalis) prior to either a stressor or no stress (water immersion test) was able to confer anxiolytic properties independent of whether stress was present, as assessed by an elevated maze plus test.[36] When looking at NGFR and Arc mRNA levels, their decrease during stress was attenuated with Lavender aroma but during the nonstressed period they were slightly attenuated (of which the authors thought that Lavender may be inducing a stress response).[36]
When isolating linalool, oral ingestion of this compound at 125mg/kg does not appear to have anxiolytic properties,[32] although it appears linalyl acetate may be a prerequisite with anxiolysis only resulting from synergism of these two molecules.[37]
One study in sheep noted that while exposure of lavender oil (via respiratory mask) to calm sleep reduced nervousness and agitation, that in a subset of sheep deemed as nervous exposure to lavender augmented the nervousness.[38] The authors hypothesized that genetic differences in anxiety may mediate these effects, but did not conduct mechanistic studies.[38]
Lavender, in research animals, appears to be associated with anxiety reducing properties independent of the presence of a stressor
An oil preparation known as Silexan (active component of the brand name LASEA) appears to be approved in Germany for the purposes of restlessness with anxious mood.[8]
One multicenter study using Silexan (80 mg) against an active control of Lorazepam (0.5 mg) in persons with generalized anxiety disorder over 6 weeks noted that anxiety (as assessed by Hamilton Anxiety Rating Scale) was reduced to a comparable level with the benzodiazepine reference drug (46% relative to baselin) and with Silexan (45%).[31] This study did not have a placebo control and similar potency was noted on other measurements (SF-36, SAS, and PSWQ-PW), and no sedation was noted with Lavender ingestion.[31] Anxiolytic effects have been noted in another trial with Silexan, where the lavender oil reduced anxiety and improved sleep to a greater degree than placebo and was associated with more responders (76.9% versus 49.1%).[39]
A study in 47 persons with somatization disorder, PTSD, or neurasthenia using Silexan at 80mg daily for 6 weeks noted significant reductions (relative to baseline) in depressed mood (57.4% of sample), sleep disorders (51.1%), restlessness (61.7%), and anxiety (44.7%) and significant improvements in cognitive functioning as assessed by the SF-36 mental health assessment (all subscales except body pain and general health).[40]
Oral supplemenation of 80mg of Lavender oil daily appears to have general anxiolytic properties
In students experiencing anxiety with test taking, Lavender aroma has been associated with reduced self-reported anxiety[41] and in a practical setting (Dental office lobby) there has been a reported reduction in anxiety associated with the aroma of Lavender, although only transiently.[42]
Aromatherapy with Lavender has once been demostrated to reduce anxiety in the setting of trauma, where persons admitted to ICU and given aromatherapy reported reduced anxiety and a better mood; the effects were transient and did not appear to build up over time.[43]
When looking at all evidence for Lavender, there appear to be consistent anxiolytic effects associated with supplementation although the robustness of the evidence for aromatherapy is less than desirable (due to inadequate sample sizes and blinding associated with aromatherapy).[44]
The aroma of Lavender is also associated with anxiolytic properties, but has less robust evidence than oral supplementation. Two studies suggest that there is no build up or long lasting effect, and that the anxiolysis of the aroma lasts for as long as the aroma is present