Abstract
Many herbal products are currently being marketed to the public as having a positive effect on stress reduction. Little research has been conducted on these products that provide health care professionals with the information they need to advise their patients on safety and effectiveness. This brief review looks at the available data on some of the most popular herbal supplements that are marketed as stress reducers. Many of these herbal products can cause a sedative effect. Therefore, health care professionals must caution their patients who concomitantly take a prescribed medication that causes central nervous system depression as well as those who drink alcohol with a herbal stress reducer due to a potential added sedative effect.
Keywords
Very few products have been studied with adequate scientific rigor that can help guide health care professionals when counseling patients.
Natural or herbal remedies used to treat various ailments have become enormously popular over the past couple of decades. The number of natural products that are available to consumers makes it difficult for the medical community to keep pace with the evidence supporting their effectiveness. This, in turn, makes it difficult for health care professionals to advise their patients about such products. Natural products promoted for the prevention and treatment of chronic stress are no exception. A Google search using the terms “natural products for stress” results in more than 26 million hits. Using the search terms “supplements for stress” results in more than 40 million hits. Additionally, a search on Amazon.com for “stress supplements” reveals more than 1350 different products that could be used for the prevention and management of stress, most of which were herbal products.
Stress prevention and management strategies that are recommended by many medical professionals are centered on coping techniques. These can include exercise, meditation, controlled breathing, yoga, tai chi, journaling, verbal expressions of feelings, participation in enjoyable activities, and many more. Additionally, many patients are prescribed medications to lower anxiety and thus manage stress. First-line agents used for generalized anxiety and panic disorders include duloxetine, escitalopram, paroxetine, venlafaxine XR, and selective serotonin reuptake inhibitors. 1 Scientific evidence supporting this use of herbal supplements for stress is limited. Very few products have been studied with adequate scientific rigor that can help guide health care professionals when counseling patients. The purpose of this article is to briefly review the available data published on a few of the popular herbal supplements that are marketed to help manage or reduce stress.
Kava Kava
Kava kava, derived from the kava plant, was historically used among Pacific Island cultures as a relaxing beverage. 2 More recently, Western countries have used kava as a dietary supplement for its sedative and anxiolytic properties. 2 Several studies have been conducted on kava to measure its effectiveness on lowering anxiety. 2 Meta-analyses of these studies have concluded that kava significantly lowers anxiety as measured with tools such as the Hamilton Anxiety Scale. 2 Kava, however, has been implicated in several liver failure cases which led the U.S. Food and Drug Administration to issue a consumer advisory warning in 2002 about the use of kava. Although it appears to be potentially effective for the treatment of anxiety, kava cannot be recommended at this time because of serious concerns regarding its adverse events profile.
Passionflower
Passionflower (Passiflora incarnata) is a plant that can be found in southeastern United States as well as in Argentina and Brazil. It is marketed in the United States as a dietary supplement effective for sleep disorders, nervous tension, and anxiety and is available in powder, capsule, tablet, and liquid dosage forms. 2 Passionflower has shown positive results for decreasing anxiety when tested in mice; however, only one clinical trial in humans has been published. 2 A randomized, placebo-controlled study released in 2001 examined passionflower (45 liquid drops per day) versus oxazepam (30 mg/d) in patients diagnosed with general anxiety disorder. 2 The results showed that passionflower was equally effective in the treatment of generalized anxiety disorder compared with oxazepam (P values for both groups <.001). 2 More research on the safety and effectiveness of passionflower is needed. Interestingly, in the early 1990s, Germany’s Federal Health Agency approved the use of passionflower for nervous restlessness. 2
Valerian Root
Valerian root comes from a perennial plant and is used as a dietary supplement for the treatment of anxiety and as a sedative hypnotic to treat insomnia. 2 A study published in 1988 examined the use of valerian and propranolol on their effectiveness at reducing stress when healthy volunteers were placed in stressful social conditions. The authors concluded that valerian alone and in combination with propranolol may reduce stress in healthy volunteers. 2 In another study, a valerian plus St. John’s Wart combination product was compared with diazepam in 100 randomized subjects with anxiety for 2 weeks. 2 Baseline anxiety scores were similar between the 2 groups. The results showed that the combination dietary supplement decreased anxiety symptoms statistically more than the diazepam group (P = .002), and the dietary supplement group reported statistically greater relief from anxiety symptoms compared with the diazepam group (P = .007). 2 Other studies, however, have been unable to show that valerian improves symptoms in patient diagnosed with generalized anxiety disorder. 3 Therefore, there is insufficient evidence at this time to judge the effectiveness of valerian at reducing stress or controlling anxiety. However, valerian is considered safe if used appropriately and for short-term periods (<1 month). 3
St. John’s Wart
St. John’s Wart is most commonly used as a dietary supplement for the treatment of mild to moderate depression. However, one study did compare St. John’s Wart 300 mg daily versus placebo for the treatment of social anxiety disorder. 2 A total of 40 patients diagnosed with social anxiety disorder were randomized to one of the two groups for a 2-week trial. The results showed that both groups significantly improved their anxiety levels as measured by the Liebowitz Social Anxiety Scale and the between-group difference was not statistically significant (P = .27). 2 Conclusions regarding this study, however, are limited because of poor research design.
Lemon Balm
The dietary supplement lemon balm (Melissa officinalis) has been shown to be potentially effective for disorders such as Alzheimer’s disease, colic, dyspepsia, herpes labialis (cold sores), and sleep. 3 In addition, a few small studies have been conducted to measure the effectiveness of lemon balm to induce self-reported calmness and improve mood. In one study, a dose of 1600 mg of dried lemon balm was associated with increased self-reported calmness for up to 6 hours after ingestion. 4 Another study showed self-reported calmness increased after 1 hour with a dose of 300 mg of lemon balm. 5 In 2004, a double-blind, placebo-controlled, randomized, balanced crossover designed study measured lemon balm on its effect to improve mood. 6 The results showed that 600 mg of lemon balm was effective at ameliorating the negative mood effects of a 20-minute tasked designed to increase stress. This study also demonstrated an improvement in self-reported calmness. 6 Based on these limited studies, lemon balm appears to have a positive effect in stress. Additionally, the adverse effects reported from using lemon balm appear to the low.
Conclusions
It is difficult for health care professionals to advise patients on the effectiveness and safety of many herbal supplements. Those marketed for the use of stress reduction are no exception. As with so many herbal supplements, the numbers of well-designed studies that are available for review are limited and are often conducted in a small number of healthy participants and for short time periods. Health care professionals should always ask their patients which herbal supplements they are taking, as patients often neglect to tell their providers because they perceive them to be “all natural” and therefore, safe. However, herbal products can have significant adverse effects similar to prescription and nonprescription medications and can also induce drug–herb interaction that can be harmful. Products marketed for stress reduction should likewise be used with caution and under the supervision of a health care professional. In particular, patients taking concomitant central nervous system depressant medication should be cautioned for additive effects. Likewise, patients should be advised not to drink alcohol while taking these herbal supplements (and central nervous system depressants) because of the potential for added sedative effects.