Prescription anti-anxiety medications are limited by safety problems
Prescription medications used to treat generalized anxiety include the benzodiazepines such as diazepam and clonazepam, and SSRI antidepressants such as paroxetine and sertraline. Chronic benzodiazepine use is associated with dependence, sedation and mental slowing. The SSRI antidepressants often interfere with normal sexual functioning and cause weight gain.
Wide use of herbals in response to a need for safer, more effective anti-anxiety medications
Beneficial effects of the essential oils or aqueous extracts of certain herbals including English Lavender (Lavandula angustifolia), Passion flower (Passiflora incarnata) and other herbals used to treat anxiety include a general calming effect achieved in the absence of sedation, and avoidance of the risk of tolerance or dependence with prolonged use. The differences between many anti-anxiety drugs and herbals are related to the fact that calming effects of the essential oils of Lavender and other fragrant herbals are mediated by many underlying mechanisms and do not act only on GABA/benzodiazepine receptors in the brain. The limited efficacy and safety concerns associated with many conventionally prescribed anti-anxiety medications have stimulated animal research on several plant-derived molecules that have many mechanisms of action and may lead to safer, more effective anti-anxiety medications (De Sousa et al 2015)
Inconsistent findings on Lavender
Oral preparations and essential oils (e.g., used in massage or aromatherapy) derived from several species of Lavender and other fragrant herbs are widely used to treat anxiety however research findings are inconsistent. Very few placebo-controlled studies have been done on different preparations of Lavender for anxiety, most studies are small or methodologically flawed and reported findings are often inconclusive. A review of randomized clinical trials reported that oral preparations of Lavender may be more effective than aromatherapy or topical application of the essential oil (Perry 2012).
Different effects from aromatherapy using Lavender or Rosemary
Some studies report significant anxiety-reducing effects in response to Lavender or Rosemary aromatherapy. A randomized controlled trial evaluated changes in electroencephalographic activity and subjective emotional states in 40 adults exposed to Lavender or Rosemary aromatherapy. Individuals receiving lavender aromatherapy showed increased activity in the beta frequency range (12 to 30 cycles per second) and reported decreased overall anxiety. Patients receiving rosemary aromatherapy showed decreased frontal alpha and beta power and reported diminished anxiety and increased alertness. These findings show that lavender aromatherapy promotes a relaxed drowsy state, while Rosemary aromatherapy promotes a relaxed alert state. Although other essential oil preparations are sometimes used to treat anxiety, there is not enough evidence to support their use.
Promising findings for Passion flower
Passion flower (Passiflora incarnata) contains an active ingredient called chrysin that has been demonstrated to bind to benzodiazepine receptors in the brain resulting in a general calming effect. Although Passion flower extract is commonly used to treat anxiety, few double blind placebo-controlled studies have been done. In one small study, Passion flower extract 45 drops per day and oxazepam (a benzodiazepine) were equally effective in reducing generalized anxiety. Patients taking oxazepam reported significant impairments in job performance at doses that lowered anxiety however there were no reports of performance impairment among patients taking effective doses of Passion flower extract. Another study reported similar findings when comparing Passion flower with the SSRI sertraline in patients with generalized anxiety (Yeung & Hernandez 2018).
Few safety issues
Different species of Lavender are well tolerated and are not associated with serious adverse effects or toxic interactions. Mild transient adverse effects irritation to the skin and a mild photo-sensitive rash, have been reported when Lavender and other essential oils are applied topically. There are a few reports that Lavender may increase the risk of bleeding when used together with an anticoagulant. Because of potential synergistic interactions, individuals taking an anti-seizure medication or a benzodiazepine should exercise caution when using the essential oil of Lavender or other calming herbals.