Lavender as a Treatment for Stress and Anxiety
The American Psychological Association reports that in the past 5 years 44% Americans have reported that their stress levels have increased. Not only is short-term stress on the rise for Americans, but chronic stress is as well (Clay, 2011). When under stress, the body produces extra cortisol, a hormone produced in the adrenal glands. Almost all cells within our bodies have cortisol receptors and an increase in production of this hormone can lead to a large variety of physiological13 symptoms we associate with stress (Cortisol, 2017). Stress can lead to anxiety disorders, which are the most common mental illness in the United States, impacting 18.1% of the population every year (Facts and Statistics, n.d.). Figure 1 shows this relationship between stress, chronic stress, and anxiety. Anxiety impacts Americans of all ages and can be caused by a variety of factors including home life, work life, and school life. Combined, stress and anxiety create conditions that put additional strain on the body and increase inflammatory hormones. The increase in inflammatory hormones can in turn increases the risk for cardiovascular events and cancer risk (Mohney, 2018).
With rates of stress and anxiety on the rise, and the long-term impacts of stress becoming more well-known, people across the globe have begun investigating a solution to these conditions. One pharmacological12 solution are anxiolytic3 drugs such as benzodiazepine. Benzodiazepines are a class of prescription medications that work by modulating9 the endogenous6 neurotransmitter Gamma Amino Butyric Acid (GABA). GABA is an inhibitory neurotransmitter that works to slow down functions within the body (Reconnexion). However, drugs like benzodiazepine can come with side effects such as sedation, headache, and ataxia (Lippa). Additionally, research has shown that some anti-anxiety medications can cause dependency (Tyrer, 1999). Fear of side effects or dependency may cause some anxiety sufferers leave their symptoms untreated.
Recently there has been a surge in the popularity of Complementary and Alternative Medicine (CAM), which utilizes non-pharmaceutical treatment methods such as aromatherapy and essential oils. One possible reason for the surge in CAM popularity, specifically aromatherapy, is its non-invasive nature with little to no known side effects (Perry, 2016). Aromatherapy using lavender, peppermint, clary sage, and bergamot essential oils has been found in several studies to decrease cortisol levels within the body (Myung-Haeng et. al. 2014) decreasing the symptoms that we associate with stress. Due to evidence showing lavender’s many benefits including analgesic2, carminative4, anti-depressive, anti-inflammatory and anxiolytic 3 properties, it has become a highly researched essential oil in aromatherapy, specifically in research on stress and anxiety (Babaheydari & Soureshjani, 2014).
Lavendula angustifolia mill (lavender) is a shrub cultivated in France, Spain, Portugal, Hungary, the UK, Bulgaria, Australia, China and the USA. Although it was traditionally grown for its aromatic inflorescence7, lavender also works to facilitate the action of GABA within the brain. Lavender is thought to act on the GABA receptors in a way similar to many pharmacological anxiety medications. One prescription drug in the benzodiazepine class commonly used for anxiety, panic attacks, and insomnia is Diazepam. Diazepam was launched in 1963 as Valium, and has since become one of the most frequently prescribed medications in the world; it is still yearly in the top 200 most prescribed medications. A study by Babaheydari et al. utilized molecular docking to predict how molecules may bind to proteins or GABAA receptors within the body. Molecular docking techniques use a 3D computer or graphic systems to create models of chemical structures of a protein and a receptor; it then takes the models and determines how well they fit together. The better the fit the greater the effects the protein will have on the receptor. (Babaheydari & Soureshjani, 2014).
Through molecular docking, it was found that the proteins within lavender dock on the GABAA receptors in very similar ways as diazepam, amobarbital, and phenobarbital. This similarity in docking between lavender and benzodiazepine drugs creates similar effects within the body, proving that lavender decreases stress and may be a possible substitute to pharmacological medications. Additionally, patients using lavender report fewer or no side effects compared to medications like diazepam (Babaheydari & Soureshjani, 2014).
Outside of the United States, research has led to approved forms of lavender being used to treat anxiety. Silexan is a patented active substance from the Lavandula angustifolia flower (lavender) that is produced following steam distillation. Silexan is the active ingredient in a drug named Lasea. Lasea is an oral treatment for anxiety that has been approved for use in Germany. When compared to benzodiazepine Silexan was shown to have similar effects in patients suffering from General Anxiety Disorder (GAD). Using previous research Schuwald et al. sought to prove the molecular rationale for the clinical use of Silexan using mice. Male and female mice were given either Silexan or pharmacological anxiety treatments for several days then monitored to track anxiety and sleep. Intracellular Ca2+ measurements were taken during the study to look at how Silexan impacts the brain on a molecular level. These samples were taken via hippocampal neurons since the hippocampus has a large role in the regulation of emotions and anxiety. (Schuwald et al. 2013)
After careful observation and data collection it was shown that there are similar modulations within the brain for both traditional anxiety medications as well as Silexan. In male mice both treatments demonstrated consistently lower levels of anxiety when the mice performed a maze task. In female mice researchers found that the mice taking Silexan demonstrated sleep promotion while the mice taking other anxiolytic drugs demonstrated sedation. Within a murine10 synaptasome14, Silexan inhibited KCL and increased Ca2+ that work with the voltage gated calcium channels in a neuron. However, while both Silexan and traditional anti-anxiety medications act upon the voltage gated calcium channels, they do so in different ways, and at different binding sites. Silexan significantly inhibits the voltage gated calcium channels that are dependent on KCL within the hippocampus. This inhibition makes it more challenging for an action potential to be signal for cortisol to be released. Similar to the traditional medications though, the inhibition with Silexan was found to be dose-dependent. (Schuwald et al. 2013)
Cumulative research has proven that traditional anxiety medications and lavender both seek to decrease anxiety by increasing efficiency of GABAA receptors on neurotransmitters. Diazepam is a positive allosteric1 modulator that binds to the benzodiazepine site on the GABAA receptors to enhance inhibitory activity within the body (Riss et al. 2008). With the increase of GABA binding in the neuron’s receptor, the inhibitory effects in the hippocampus are greater, which leads to decreased stimulation of the adrenal glands and thus a decreased production in cortisol. With less cortisol in the body, patients report less symptoms associated with stress. Recent studies show that the protein structures in lavender bind with the GABAA receptors in a similar way to traditional anxiety medications like diazepam. The similarities lavender binding to GABAA receptors create similar effects as bendoziapines within the body. When researched further it was discovered that other terpenes15 with similar chemical structures do not exhibit similar modulation on the GABAA receptors, making the anxiolytic effects excusive to lavender (Babaheydari & Soureshjani, 2014).
As the evidence for efficacy of lavender to reduce stress and anxiety strengthens, and this form of CAM becomes more popular, an entirely new population of anxiety sufferers may begin to seek treatment. One side effect of pharmacological anxiety treatment is sedation which can be a deterrent for those living with anxiety. However, research has found in mice that lavender does not create sedation but rather sleep promotion (Schuwald et al. 2013). By providing an alternate treatment for anxiety those living with an anxiety disorder can lower cortisol levels and prevent pathogenesis11 of health problems.