Acupuncture for Anxiety

SUMMARY

This review aims to examine the volume and quality of the evidence base which supports the use of acupuncture in the treatment of anxiety disorders. A literature review was conducted using Pubmed, Google scholar, AMED, BMJ, Embase, Psychinfo, Cochrane library, Ingenta connect, and Cinahl databases. Keywords were “anxiety,”“anxious,”“panic,”“stress,”“phobia,” and “acupuncture” limited to year 2000 onwards and English language where available. The quality of research examining the use of acupuncture in the treatment of anxiety disorders is extremely variable. There is enormous variety regarding points used, number of points used in a session, duration of sessions, frequency of treatment and duration of treatment programme. While the generally poor methodological quality, combined with the wide range of outcome measures used, number and variety of points, frequency of sessions, and duration of treatment makes firm conclusions difficult. Against this, the volume of literature, consistency of statistically significant results, wide range of conditions treated and use of animal test subjects suggests very real, positive outcomes using a treatment method preferred by a population of individuals who tend to be resistant to conventional medicine.

Introduction

Anxiety is defined as “The apprehensive anticipation of future danger or misfortune accompanied by a feeling of dysphoria or somatic symptoms of tension. The focus of anticipated danger may be internal or external”[1]. However, the Diagnostic and statistical manual of mental disorders (or DSM IV) goes on to state that it is better described as a collection of conditions [1], being:

• 1Panic attack
• 2Agoraphobia ± history of panic disorder
• 3Panic disorder ± agoraphobia
• 4Specific phobia
• 5Social phobia
• 6Obsessive compulsive disorder (OCD)
• 7Posttraumatic stress disorder (PTSD)
• 8Acute stress disorder
• 9Generalized anxiety disorder
• 10Anxiety disorder due to a medical condition
• 11Substance‐induced anxiety disorder
• 12Anxiety disorder not otherwise specified

There are also suggestions that symptomology associated with anxiety disorders have to be understood in the context of the cultural background of the patient [2]. Others take this further, suggesting that biological and genetic variations between ethnic groups, including those directly involved in the structure and function of the brain, can result in variations in psychiatric conditions and hence the treatments of these individuals [3].

Anxiety is estimated to cause 1% of all disability adjusted life years lost worldwide in the form of PTSD, OCD and panic attacks [4]. Anxiety in the UK affected 16.8/100 population in 2004 [5]. In China, Japan, and Korea, it is common practice to treat emotional, psychological and spiritual conditions, including anxiety, stress, depression, and insomnia, with Traditional Chinese Medicine (TCM) acupuncture [6]. This management approach, and the use of complementary and alternative medicine (CAM) as a whole, has been identified as a growing trend within the Western world [7, 8], with some reports suggesting that those individuals with psychiatric conditions are more likely to use CAM than those without a psychiatric medical history [9]. Despite this trend, there is, as yet, no evidence to suggest that the compliance with CAM is superior to that with conventional management [10].

There is an ongoing tension between the Western and the TCM approach to acupuncture. TCM methodology has a history stretching back over 3000 years [11], but due to its antiquated assessment techniques and terminologies, its “prescientific notions”[12], it has been modified through evidence based medicine and research into the modern Western style among many health professionals who have learnt to use acupuncture as an adjunct to their training. Western acupuncture, being underpinned by anatomy, neurophysiology and an orthodox medical model, is the paradigm used by many health care professionals due to its growing evidence base, relative cost‐effectiveness and ease of use. That its scientific evidence base is increasing is something that has been acknowledged for over a decade [13].

Aims

The aim of this review is to examine the research that has investigated the use of acupuncture in the treatment of anxiety disorders. This will give readers a greater understanding of the quality and quantity of evidence which supports (or refutes) acupuncture as a worthwhile treatment for these conditions. The quality of articles will be considered in light of repeatability (i.e., point location, duration, frequency of visits, etc.), participant allocation (i.e., randomization, sample size, etc.), data acquisition (i.e., objective vs. subjective measures) and analysis techniques used. It is not the aim of this review to offer explanation of TCM diagnosis or treatment rationally, nor to offer an explanation of why the points described were chosen, nor to suggest a mechanism of why they work. This review deals only with the points that have been chosen and proven to be effective in the literature, and a critique of the standards of research at this time.

Methods

A literature review was conducted using PubMed, Google scholar, AMED, BMJ, Embase, Psychinfo, Cochrane library, Ingenta connect and Cinahl databases. Keywords used were “anxiety,”“anxious,”“panic,”“stress,”“phobia,” and “acupuncture” limited to year 2000 onwards and English language where available. The search was not limited to human subjects. Results were combined and abstracts obtained, reviewed and relevant articles sent for. Reference lists were also examined to ensure seminal articles were included. Initial searching provided several million articles, which was reduced through combining keywords and then by reviewing abstracts. Unfortunately, many foreign language articles were excluded also, although a sample of their abstracts were included in providing an insight into the research worldwide. Previous review articles were used to obtain their references to ensure conclusions drawn were first‐hand where possible. In total 32 relevant articles were identified.

Results

This section will be divided into subsections to deal with the literature in terms of components of articles, e.g., issues regarding the study sample, in terms of recruitment, randomization, blinding, sample size, etc. The final section with examine the evidence base obtained through the use of the animal model.

Prior to this, a note must be included regarding the exclusion of foreign language articles. While the articles themselves were excluded, often the abstracts were published in English, allowing an insight into the areas of treatment dosage, point selection, etc. For example, Zhu and Ding [14] reviewed the literature from 1994 to 2008 and state from this that GV20, PC6, HT7, SP6, and ExHN3 were the points most commonly selected. They suggested that the acupoint selection was based on treatments directly effecting the heart and brain, which emphasized the importance of the Zang and Fu organs in TCM.

Su and Zhu [15] performed a literature search of articles 1996–2004 and agree with the points selection, however, they suggest that the emphasis of treatments should be pushed towards the brain, with the Du meridian, with local head acupoints. They go on to state that the evidence needs to be improved with an increased sample size, randomization and multicenter trials.

Wang and Zhang [16] offer the opinion of an expert, Professor Sun Shen‐Tian, that GV 20, EX‐HN3, “emotional area” and “Zone 1 of Sun's abdominal acupoints” are often selected to aid in “malfunctions of the brain.” While Western literature has a heavy emphasis on the research of control groups, randomization, statistical analysis, etc., and very rarely offers an expert opinion outside an editorial piece, the Eastern literature places a greater emphasis on the knowledge and experience of their experts in particular fields. It would be reasonable to suggest that this difference is cultural, as the East has a tradition of martial arts schools, etc with a master teaching their particular style.

The debate regarding treatment dosage is also a hotly contended issue in the East, with both over and under treatment acknowledged as potentially worsening the patients condition, while currently lacking agreement as to the correct treatment dosage [17]. This is also suggested as being an area that desperately needs a large research undertaking to improve standardization and provide optimal treatment [18, 19].

It must be noted that, as these statements are taken from the translated abstracts, it is impossible to conduct any meaningful analysis of the quality of the research detailed above. However, as an indication of the general trends, the abstracts show similar patterns of concern within the research community of the East and the West. These abstracts show the same questions regarding point selection, treatment dosages, treatment frequency, standardization, etc. are actively investigated world wide.

Methodological Components

Participants were either healthy volunteers or patients who consented to join the trials, most often taken from a convenient, available population such as students at university [20], although some general population recruitment through advertising on local media and posters did occur [21, 22]. Many introduced a randomization element [20, 22, 23, 24, 25, 26, 27], including some quasi‐randomization [20, 26], although it is often not described [24, 25] and some included some degree of blinding the assessor and/or analyst [24, 25, 27], although obviously blinding the acupuncturist is impossible. Additional to these current findings, it has been shown in the past that the randomization procedure is poorly described by previous authors [6]. It must be stated that the Wang et al. [25] study states it is blinded, but does not describe the method used to ensure this. It must also be noted that the animal studies [28, 29] also provided statistically significant results in a population where randomization and blinding are considered absolutes.

Sample size was exceptionally variable, ranging from 240 patients [30] to 4, with one drop out [31]. Generally, large study populations were used in the majority of the research [20, 22, 23, 24, 25, 26, 32, 33].

Many articles [11, 20, 22, 23, 24, 25, 26, 27, 28, 29, 34] described the location, duration and frequency of visits with sufficient specificity to make the research repeatable. In these articles, the rational given for point selection was generally poor. Exceptions to this include the Karst et al. [24] study, who described the methodology well, stated that the points selected had been documented to reduce preoperative anxiety [25] to justify this selection. The article they cited [25] described the rational for TCM and non‐TCM point selections, based on a previous pilot study, plus reasoning from the Shanghai college of traditional medicine, as well as providing the methodology used to a degree that made the procedure repeatable.

Further articles failed to describe the points at all, often referring to TCM methodology of an individually based treatment [32, 35] or failing to mention the technique at all [21, 29]. This stems from the problem that conversion of a western diagnosis to a TCM is inexact, often resulting in several different TCM diagnoses for what western medicine would count as the same condition [36]. Some practitioners go further, stating that no two individuals could be treated using the same methodology [35].

Review articles often had this lack of detail, with an example of this being Samuels et al. [10], who describe the quality of the research and the evidence behind the use of acupuncture well, but then fail to describe any acupuncture points at all, leaving the reader without the knowledge of which points lead to an efficacious outcome. Another example, being van der Watt et al. [37], who aimed to review the literature regarding complimentary and alternative treatments both anxiety and depression. Due to the extremely broad scope, the result is the most superficial of references to acupuncture, consisting of two articles [22, 27].

In contrast to this, the excellent Pilkington et al. [8] review describes the points used in most studies, but does not give any form of analysis as to which points were used most often to the best effect. This is an unsurprising finding as the methodological quality of many studies, combined with the extensive variety of points used, makes it very difficult to produce anything other than point‐frequency based inferences. This Pilkington review has been repeated with updated, more recent references in the same style [38].

These problems are compounded on several levels. Often the educational background of the acupuncturist is also lacking [20, 23–26, 28, 29, 31, 32, 34], which would reasonably lead to questions regarding the non‐justification of point selection. There is also the on‐going difficulty of the transition between a Western diagnosis of anxiety and the TCM diagnosis system, where the treatments are modified so extensively. In one article the acupuncturist was an individual described as a “master acupuncturist”[21], the “director of an acupuncture training programme and clinic”[21]. Another was a doctor of oriental medicine with 4 years postgrad TCM clinical experience [22]. A further study described a specialist physiotherapist who had performed “over 2000” treatments of this type [26]. The Liu et al study [30] describes a treatment methodology based on the acupuncturist selecting between 3 and 6 points from a choice of 11, giving the very real possibility that members of the same study group receiving completely different treatments. While some practitioners can be expected to have knowledge and experience, but there is no evidence that some of the individuals who develop unique, tailored treatments, based on TCM diagnoses, have the experience to do so.

The data acquired was generally of high quality, with objective, validated measures used in the vast majority of studies. These ranged from the Visual Analogue Scale at the most basic level [24, 26, 31], through the Hospital Anxiety and Depression Scale (HADS) [26, 27], Hamilton anxiety scale [23], State‐trait anxiety inventory [25], to functional MRI [34]. An article focused on PTSD specifically used the Posttraumatic Symptom Scale‐Self Report [22]. The Patterson et al. [39] study describes the development of new outcome questionnaires within a multibedded, high volume, high flow rate clinic (with 17% of patients describing psychological conditions), where a “senior practitioner” performs a TCM assessment of the individual before passing their treatment to a practitioner. These questionnaires were proven reliable and validated within this population.

Analysis was carried out and results provided regarding their statistical significance for the vast majority of cases [20, 22, 23, 24, 25, 26, 27, 28, 29, 31, 34, 39].

Animal Studies

There is growing evidence regarding acupunctures therapeutic effect within animals. Behavioral measures, specifically designed to ascertain levels of stress and depression, such as the elevated maze test (a cross shaped apparatus 50 cm above the floor with four 40 cm long, 10 cm wide arms) where time spent and number of entries into the “open” two arms compared to the “closed” two arms (which have 30 cm tall enclosing walls) over 5 min is indicative of anxiety levels. Another test is the sucrose intake test, where subjects with matched food intakes differ in consumption of sucrose solution, with resulting differences in body weight proportional to levels of anxiety, with low weights linked to higher anxiety levels. Further to this, animal studies offer the opportunity to examine the biochemical effect of acupuncture through immunohistochemistry performed directly to the brain tissue for anxiety and/or stress‐induced depression markers, most often, but not exclusively, markers related to neuropeptide Y.

There is an obvious concern that the use of acupuncture, which requires the test rat to be immobilized for the insertion and duration of the needling, would in itself cause anxiety. The implications of this have been researched and found that, even when the rats are introduced to regular immobilization, thus somewhat inuring their response, they have an experience consistent with those rats who do not become desensitized [40].

A well designed study by Kim et al. [28] described a four arm experiment which compared a “natural” group, which received no stresses, a control group, acupuncture group (Pericardium 6) and sham acupuncture group, which experienced chronic mild stresses [41]. They examined both behavioral (elevated maze test and sucrose intake test) and biochemical markers to assess the treatment outcomes. This study showed that the stress experienced by the control group had a statistically significant effect (P < 0.001), but that there was a statistically significant difference between the control group and the acupuncture group in terms of bodyweight (P < 0.05) and immunohistochemical markers (P < 0.001). There was no statistical difference between the control and the sham acupuncture group (P < 0.071). There was also a nonstatistically significant increase in the volume of sucrose solution consumed, a behavioral marker of stress‐induced depression [42].

Chae et al. [43] examined whether acupuncture could help to alleviate the significant levels of anxiety caused by nicotine withdrawal during smoking cessation. First, three groups of rats were given repeated injections of nicotine to develop an addiction, with one additional group injected with saline to act as the “normal” group. Of the addict rats, one group became the control, one the acupuncture group (Heart 7) and the final group the sham acupuncture group (Stomach 36). There was a statistically significant difference between the control and the acupuncture group, both on the elevated maze test and the immunohistochemical markers during dissection (P < 0.05) and no statistical difference between the sham acupuncture and the control group.

Park et al. [29] studied the use of acupuncture in anxiety within a population of rats. In an experimental study involving maternal separation from day 3 to day 14 among infant rats, result suggested a statistically significant increase in anxiety on the elevated maze test (P < 0.05) and immunohistochemical markers (P < 0.05). As with other animal studies, Park et al. [24] found that the use of a sham acupuncture point, in this case Stomach 36, had no significant effect. The acupuncture point used in this study (Heart 7) had a statistically significant reduction in both anxiety (P < 0.05) and immunohistochemical markers (P < 0.01).

Finally, Lee et al. [44] gave their experimental group of rats needling to Pericardium 6 in a well designed study examining whether acupuncture could be used prophalactically. The used the elevated maze test, plus the forced swim test, where a cylinder is filled with water to a depth that prevents the rat reaching the bottom. Periods of immobility, not trying to get out of the cylinder, are linked to anxiety/depression. The control and experimental groups were injected with corticosterone, which was proven to increase anxiety (P < 0.05) and immunohistochemical markers (P < 0.05), with the acupuncture groups receiving their treatment in advance. The acupuncture group had a significant reduction in anxiety (P < 0.05) and immunohistochemical markers (P < 0.05) while the sham acupuncture points were proven ineffective.

These results, and those described above, suggest that, in an animal model, both behavioral and biochemical marker changes occur to reduce anxiety by statistically significant levels, in a study population which is immune to the placebo effect. The animal model is also considered the gold standard in terms of randomization and standardization of study population.

Discussion

Prior to starting the discussion proper, a major factor in this review must be acknowledged, being that there is a widely acknowledged difference between the Eastern and Western approach, with Eastern treatment dosage following a different prescription, especially as regards frequency of treatment, which is far higher than the Western equivalent. Had it been possible to access the Eastern literature, this difference would be highlighted.

The quality of the research pertaining to the use of acupuncture in the treatment of anxiety disorders varies greatly. Results are almost universally positive, but also the almost universally poor quality of the methodology reporting [45]. This issue is highlighted as regards reporting the frequency, duration, point location, consistency of treatment, etc, and results in many studies that would otherwise prove an excellent source of information being reduced to another place to “get the gist” of the use of acupuncture to treat anxiety problems. There is also the additional layer of complexity associated with the fact that acupuncture in itself is proven to induce both pain and anxiety in some patients [20, 46].

Bearing in mind these points, to perform a literature review is difficult in the extreme. A literature review should aim to review, critique and recommend a course of action, or describe a range of options, highlighting the benefits and detriments associated with each. However, all literature reviews carried out to up to this point offer review and critique, but fail to provide a treatment recommendation, instead providing only a useful resource to clinicians who wish to obtain the literature for themselves and divine their own conclusions. Ultimately this situation is will remain unchanged as there is no single recommendation available, and, more importantly, an enormous number of options with little rationale for which would provide the best outcome.

It could reasonably be argued that the question of what constitutes an adequate dose [47] is a key component of this review. What defines the correct point to use for a particular condition, the number of points (and therefore needles) to use, sessions per week, number of sessions, which constitute a treatment episode and finally, the duration of the acupuncture treatment? These details are paramount to determining “the optimal acupuncture technique,” and therefore these details will be examined individually with the aim of providing some clarity into what the most frequently used method is, thus offering clinicians a greater evidence base in the method they use.

To gain an understanding of what is the correct technique, Table 1 illustrates a frequency table listing the points used and the number of articles in which those points are used, obtained from the literature reviewed previously. Please note that all these results are taken from articles in which the treatment group had a beneficial effect and that often the points are used in synergy with other points. It is not the aim of this table, nor this literature review as a whole, to provide recommendations for the combinations to be used. A final point to highlight is that, as mentioned throughout the previous sections, the different articles varied in the details described, resulting in some discrepancy between each graph, i.e., number of points used = 19, sessions per week = 15, number of sessions = 19, and duration of session = 16.

Table 1.

Table showing frequency of points used (animal studies specifically identified)

	BL 14	BL 15	BL 18	BL 20	BL 21	BL 23	BL 62
Bladder	1	2	2	2	1	3	2
	GB 5	GB 8	GB 13	GB 20
Gall Bladder	1	1	1	2
	PC 6	PC 7
Pericardium	6 + 2 animal	1
	LI 4	LI 11	LI 20	LI 24
Large Intestine	2	2	1	1
	HT 7
Heart	7 + 1 animal
	GV 4	GV 20	GV 24
Governor Vessel	1	4	1
	ST 25	ST 36
Stomach	1	2
	KI 3	KI 6
Kidney	1	1
	SP 6
Spleen	2
	LR 2	LR 3
Liver	1	5
Ear points
Kidney	1
Heart	1
Shenmen	3
Tranquiliser	2
Master Cerebral	2
Relaxation	3
Extra point
Yintang	4

As is shown in Table 1, the points, which were used the most frequently were PC6 (8), HT7 (8), LR3 (5), GV20 (4), and Yintang (4). It is worth noting that only PC6 and HT7 were used in animal studies (PC6 twice and HT7 once). The fact that these points should be used so frequently in research from both TCM and Western acupuncture perspectives, combined with the results from the animal studies suggest that these points should be focused on in future research.

The next area to be examined is regarding the number of points used to treat an individual condition, which in this case refers to anxiety disorders, and is displayed in Figure 1. As can be seen, when treating anxiety, the most frequently used number of points is three, closely followed by one. This data is obviously limited to the acupuncture in anxiety research as reviewed in this article, but the general guidance is that acupuncture “norm” is between five and fifteen needles [12]. However, this guidance appears just as arbitrary as other guidance regarding point selection, etc. This repeated use of an arbitrary figure could easily be suggested as being the core problem facing acupuncture research today.

Figure 1.

Number of points used in the treatment of condition as described in articles reviewed.

The required number of sessions per week, again in the treatment of anxiety, is shown in Figure 2. As can be seen, a frequency of one session per week or three sessions per week are the most common treatment regimes used. It must be noted that, while two studies included seven sessions weekly, both were animal studies. Surprisingly, the six treatment sessions per week article involved human subjects.

Figure 2.

Number of sessions per week as described in the articles reviewed.

Another factor is regarding the number of sessions, which constitute a treatment episode. This data is displayed in Figure 3. As can be seen, a set of ten sessions was the most commonly used treatment regime. This was closely followed by a single session and a set of thirty session treatment regimes. The articles describing a single treatment session were universally describing acupuncture used in prevention of situational anxiety, prior to an operation or dental intervention. It must be noted that the highest number of sessions to constitute a treatment intervention, being 40, was actually a set of ten session treatments repeated four times due to continued improvements.

Figure 3.

Total number of sessions constituting a treatment episode as described in the articles reviewed.

The final aspect of acupuncture is regarding the duration of the acupuncture treatment itself. This data is displayed in Figure 4. As can be seen, a half hour session was the most commonly used treatment regime. This was closely followed by a 25 min session and 30‐second treatment session. The 30‐second sessions were both described in animal studies, which raise interesting points in itself due to the statistically significant results obtained through such a rapid intervention.

Figure 4.

Duration of each session, as described in the articles reviewed.

Conclusion

Research into the use of acupuncture in the treatment of anxiety disorders is progressing in an uncoordinated manner, with generally poor methodological reporting and rationale for point selection often lacking. The conflict between the Eastern and Western acupuncture theoretical paradigms adds to the levels of confusion presented to the practitioner searching for a gold standard treatment. It is reasonable to suggest that this is compounded further by the obvious difficulties presented by language limitations encountered by most practitioners. These practitioners would not be able to access the vast majority of literature, which is being produced by those who speak other languages.

As such, this literature review aims to present an overview of the state of research into this area as it stands at this time, combined with a degree of guidance for the practitioner regarding point selection, number of points used, sessions per week, duration of sessions and duration of the treatment intervention, and to provide an evidence base for those seeking to gain a rationale for the points that they use.

Each paper showing statistically significant effects directly attributable to an acupuncture treatment lends weight to the use of acupuncture to significantly reduce the symptoms of anxiety disorders, using both human and animal subjects. To some extent, despite the methodological criticisms, it is this central point that must be focused upon. There is evidence that acupuncture is comparable with CBT, which is a common intervention in the treatment of this condition [22, 43], but in a setting and environment in which most patients seem to find less stressful, and are well known to access voluntarily in preference to regular medical avenues. Finally, it must be a priority amongst researchers worldwide to provide consistent, evidence‐based recommendations regarding the adequate dose required for acupuncture to have a therapeutic effect.

Conflict of Interest

The author has no conflict of interest.