Complementary and Alternative Medicine in the Treatment of Anxiety and Depression

A number of complementary and alternative interventions are currently being used to treat anxiety and anxiety disorders. For the purposes of this review, they will be grouped as follows: herbal interventions, nutritional supplements and aromatherapy; cognitive interventions, including mindfulness-based stress reduction (MBSR) and meditation; and physical interventions such as acupuncture.

Herbal Interventions, Nutritional Supplements and Aromatherapy

Werneke et al.^[2*] conducted an extensive database search and identified 2007 studies of herbal remedies and nutritional supplements in the treatment of psychiatric disorders. The authors found that kava (Piper methysticum) was the most researched remedy for anxiety and that there was good evidence for its anxiolytic effect. A Cochrane review reported by Pittler and Ernst,^[14] which included 11 RCTs involving 645 patients, showed that kava is the only herbal remedy that has been proven to be effective in reducing anxiety. All of these trials showed the anxiolytic effects of kava to be superior to those of placebo. In a recent review, Ernst^[15*] warned that, although it has been shown to be effective in reducing anxiety, kava cannot be recommended for clinical use because of an association with hepatotoxicity, which has led to its withdrawal from the UK market. He emphasized the importance of conducting large, long-term clinical trials to investigate the effects of herbal medicines, which are usually moderate and tend to appear after prolonged periods of use.

Two separate Cochrane reviews investigated the effectiveness and safety of treating anxiety disorders with valerian and passiflora. The valerian review^[16**] identified one randomized controlled trial involving 36 patients with generalized anxiety disorder that was eligible for inclusion. This study found that patients taking diazepam experienced significantly greater improvement in self-reported anxiety symptoms than those in the valerian and placebo groups, with no significant differences in reported side effects between the three groups. The other review, also conducted by Miyasaka et al.,^[17**] identified two passiflora versus benzodiazepine studies eligible for inclusion with a total of 198 participants, but no findings reached statistical significance. The authors concluded that there is insufficient evidence available to draw any clear conclusions regarding the efficacy or safety of either valerian or passiflora in treating anxiety disorders.

Aromatherapy is concerned with the psychological, physiological and pharmacological effects of essential oils introduced by means of inhalation, olfaction and dermal application. The precise definition of aromatherapy, however, remains problematic. Perry and Perry^[18*] consider the terms essential oil therapy or phyto-essential-pharmacology to be more precise than aromatherapy, because effects are not necessarily related to the aromas only. Some practitioners view aromatherapy as holistic medicine, which treats soul, spirit and body, whereas a small number of research groups focus on fragrance compounds and essential oils as medicinal agents and aim to elucidate their modes of action. The pharmacology behind the actions of most essential oils remains uncertain, however. Buchbauer and Jirovetz^[19] proposed a universal definition of aromatherapy as the therapeutic use of fragrances or of volatile substances to cure and mitigate or prevent diseases, infections and indispositions only by means of inhalation, in the belief that this definition has helped to promote scientific work on aromatherapy and the biological effects of essential oils.

In their review of reports published in English language medical journals, Perry and Perry^[18*] found only one small open-label study of aromatherapy in the treatment of psychiatric patients diagnosed with anxiety and depressive disorders. Aromatherapy was combined with massage and essential oils were individualized.^[20] The study's author reported that six of the eight participants experienced reduced anxiety and improved mood over an 8-month period of use. It is not possible, however, to distinguish whether this improvement was due to massage, the essential oils chosen, psychotropic medications (which were not standardized), or other factors. The study is also limited by the lack of a control group.

A recently reported study of the effectiveness of aromatherapy in the management of anxiety in patients with cancer^[21] was carried out in four cancer centres and a hospice in the UK, where 288 patients with cancer and with clinical anxiety or depression were randomly assigned to a 4-week course of aromatherapy massage or usual supportive care. Patients receiving the aromatherapy massage experienced a significant improvement in anxiety and depression symptoms after 2 weeks, and this was maintained at 6 weeks (64% improvement versus 46% in the control group). The difference between the groups disappeared by 10 weeks after randomization. Self-reported anxiety improved more for patients receiving aromatherapy than for patients in the usual care group at 6 and 10 weeks after randomization, whereas there was no significant difference in the improvement of self-reported depression between the group receiving aromatherapy massage and the usual care only arm. Twenty essential oils were used and individualized according to the therapist's choice of oils considered most appropriate for each person. The authors did not report which essential oils were used nor the specific dosages used. The study was unable to demonstrate whether massage or the essential oils, or both, were responsible for the improvement in mood and anxiety of patients receiving aromatherapy.

Cognitive Interventions

Toneatto and Nguyen^[22] reviewed controlled studies of MBSR for the treatment of anxiety and depression published before 2007 and found no evidence for the efficacy of MBSR in reliably reducing anxiety symptoms. The reviewed studies that reported a statistically significant reduction in anxiety or depression after MBSR did not include an active control group; positive findings were found only when waiting list or usual treatment groups were used as controls. The authors suggested that nonspecific variables may account for improvements in the MBSR-treated patients and that future studies with improved methodologies are required to test the specific efficacy of the mindfulness component of the intervention.

Meditation has a long history across many cultures. There are many types of meditation, all involving techniques for the focusing of attention. The object of focus can be an image, an idea, a word, a phrase, or one's breath. In their Cochrane review of RCTs in which meditation therapy was used as an intervention for anxiety disorder, Krisanaprakornkit et al.^[23**] focused on studies published before 2006 in which meditation therapy was compared with conventional treatments, including drugs and other psychological treatments. The review targeted meditation therapies that used concentrative meditation or mindfulness meditation to treat anxiety disorders. The two studies eligible for inclusion in the review included 45 individuals and were conducted in the USA, whereas there were no eligible studies from Eastern countries such as India and China, where many meditation techniques originated. The authors were unable to draw firm conclusions about the effects of meditation in anxiety disorders because of the small number of eligible studies. They did note that dropout rates were high in each of the studies reviewed.

In a study published after these two reviews, Lee et al.^[24] investigated the effectiveness of a meditation-based stress management programme in patients with anxiety disorder. Forty-six patients diagnosed with anxiety disorders were randomly assigned to either the meditation programme (MBSR, which included some education on coping with anxiety, exercise, muscle build up, relaxation and hypnotic suggestion) or the education programme. The education programme focused on the biological aspects of anxiety disorder, with no stress management or behaviour techniques taught. Prescribed medications were not altered during the study. The duration of the programme was 8 weeks, with 60-min sessions provided weekly. There were significant decreases in all anxiety scale scores for the meditation programme group compared with patients on the education programme. No significant improvement in measures of depression, somatization, or obsessive-compulsive symptoms was demonstrated. Limitations of the study include the possible confounding effects of administered medication, the lack of a true placebo control and the absence of any follow-up data. The authors suggest that a larger study taking into account the above limitations is needed to confirm these findings.

Physical Interventions

Acupuncture is a traditional Chinese treatment using needles which are inserted at specific points of the body and either manipulated or electrically stimulated. Traditional Chinese theory posits that acupuncture corrects the imbalances in yin and yang forces that circulate along channels in the body, and this balance is considered to be essential for good health. Two recent studies are of interest.

A randomized crossover trial conducted by Gibson et al.^[25] found statistically significant differences between acupuncture and breathing retraining, in favour of acupuncture, in a small sample of 10 patients diagnosed with hyperventilation syndrome (HVS). The authors cautioned that, although there appears to be a beneficial effect of using acupuncture to treat HVS by reducing anxiety and hyperventilation symptoms, there may be a carry-over effect after the acupuncture treatment that was not detected because of the small sample size. They suggest that a two-arm randomized trial using an acupuncture placebo might be more appropriate for further investigating the effects of acupuncture on HVS.

Another recently reported RCT evaluated the efficacy and acceptability of acupuncture for treatment of post-traumatic stress disorder (PTSD).^[26] In all, 84 patients diagnosed with PTSD were randomly assigned to one of three groups, with one group receiving acupuncture, another group receiving cognitive-behavioural therapy (CBT) and the third acting as a wait list control. A total of 61 participants completed the trial and the results suggest that acupuncture might be useful in reducing symptoms of PTSD, depression, anxiety and impairment in people diagnosed with PTSD. Treatment effects in the acupuncture group were similar to those with the group CBT intervention, and both interventions were superior to the wait listed control on all measures. Both groups also expressed high satisfaction with care, and both acupuncture and group CBT were seen as equally acceptable by participants in treating PTSD. Treatment effects were maintained for 3 months after the end of treatment in both the acupuncture and CBT groups. This initial evidence that acupuncture may be effective and acceptable for treating PTSD suggests that a larger study is indicated to evaluate this adequately. The authors suggested that a multisite trial with multiple therapists rather than a single therapist, additional control groups, treatment validation procedures and blinded outcome assessment should be considered.