Acupuncture: Powerful Placebo or Potent Pain Killer?
There is plenty of talk about how acupuncture can provide pain relief, but just how effective is it?
Chinese medicine theories and early versions of acupuncture are understood to date back thousands of years, and this is often the point put forward by practitioners and acupuncture enthusiasts alike to support its validity as a medicine. However, such a rich and long-standing history can act as a double-edged sword when placed under the stark light of scientific investigation. With roots reaching back into ancient history to a time where maintaining health was based on protection against demonic possession (1), acupuncture can make for an easy target when certain people wish to debunk it as snake oil.
But if acupuncture truly has no worthwhile benefit to our health, if all of its perceived benefits that many people swear by is nothing more than a placebo, why then after thousands of years is it still around? Surely at some point in history, its apparent lack of effectiveness should have seen it go the way of mercury, miasmas and ice-pick lobotomies. But for some reason, the placebo effect of acupuncture appears to be so captivating of both those who receive it and administer it, that it has managed to hold its ground in this increasingly pharmacologically-founded healthcare system of the modern age.
So is it really the beguiling hoax that many science-minded people and practitioners purport it to be? Or is there something specific going on at the cellular level that we are now able to gain a more insightful understanding of? How exactly do acupuncture and its modern counterpart electroacupuncture (EA) relieve pain?
“Studies over the last decade have shown that electroacupuncture activates the nervous system, alleviating sensory, inflammatory, and neuropathic pain.”
Pain in the human body occurs as a result of a complex process involving a range of biochemical substances and nerve pathways that provide us with a sensory modality that is essential for survival (2). Pain consists of three basic types: psychogenic pain that is caused by the mind and rarely the sole cause; neuropathic pain that results from damage to either the peripheral or central nervous system; and the most commonly occurring – nociceptive pain (3). This pain is sensed by nerve endings (nociceptors) that conduct a variety of different stimuli into nerve impulses which are then interpreted by the brain as the sensation of pain (4).
Just as pain can be perceived in the body in numerous ways, so too are there a number of different ways that acupuncture appears to ameliorate it. The practice of acupuncture involves the insertion and manipulation of ultra-fine needles into the body to produce healing effects (5). Electroacupuncture is a modified technique of acupuncture that incorporates electrical stimulation of the needles to enhance these benefits (6). Studies over the last decade have shown that it activates the nervous system, alleviating sensory, inflammatory, and neuropathic pain (7).
“Beta-endorphins are 18 to 33 times more potent than morphine while dynorphins are 200 more potent than morphine and 50 times more powerful than beta-endorphins."
As a result of the great deal of acupuncture analgesia research since the 1950’s, it has been well-documented that acupuncture can produce antinociceptive effects by increasing the production and release of opioid peptides in the central nervous system (8). These opioid peptides have profound effects on the body such as potent analgesia, regulation of visceral functions and modulation of the immune system (9).
These biochemical changes occur via peripheral, spinal and supraspinal mechanisms throughout the body, and result in a desensitisation of peripheral nociceptors and a reduction in pro-inflammatory markers (10). EA has also been found to down-regulate the expression of glutamate receptors which are involved in nociceptive signals (11), as well as inhibiting microglial activation that occurs during the inflammatory response and neuropathic pain (12).
Not only does the evidence reveal that acupuncture and EA promote these beneficial effects in the body, the body’s biochemistry also seems to respond according to variations in the frequency of the electrical current applied to the needles. It has been found that EA at 2 Hz stimulates the release of beta-endorphin, enkephalin and endomorphin within the central nervous system, while EA at 100 Hz releases dynorphin (13). Why does this matter? These endogenous opioids play very important roles in pain relief within the body as beta-endorphins are 18 to 33 times more potent than morphine (14), while dynorphins are 200 more potent than morphine and 50 times more powerful than beta-endorphins (15). Considering these facts, one could conclude that there is more going on with acupuncture than just a mere placebo.
“The American College of Physicians places acupuncture at the top of the list with a “strong recommendation” as a non-pharmacological treatment for low back pain.”
With the recent publication of the Acupuncture Evidence Project by John Macdonald and Stephen Janz in Australia, a standard for the effectiveness of acupuncture has now been established for specific conditions based on available research. Among the list of the 8 conditions where acupuncture is supported by strong evidence, six of them are pain-related conditions: chronic low back pain; chronic and tension-type headache; knee osteoarthritis; migraine prophylaxis and postoperative pain (16). There are a further 38 conditions for which the research is moderate, and 71 conditions for which the research is weak positive/ unclear (17).
While the list of conditions for which there is high-quality evidence may seem small, this is not necessarily due to a lack of effectiveness of acupuncture, but rather a lack of high-quality trials that stand up to scientific scrutiny. As stated in the publication, “Placebo-controlled clinical trials consistently underestimate the true effect size of acupuncture (which means that acupuncture is more effective than the type of trials used in this review show)” (18). However despite this fact, “they have still demonstrated National Health and Medical Research Council (NHMRC) Level I evidence for the effectiveness of acupuncture for 117 conditions” (19).
Clinical guidelines published in the Annals of Internal Medicine developed by the American College of Physicians (ACP) also now formally recommend acupuncture for the treatment of back pain (20). Based on quality evidence reviewed from randomised, controlled trials and systematic reviews, the ACP places acupuncture (among other treatments) at the top of the list with a “strong recommendation” as a non-pharmacological treatment for low back pain (21).
It certainly is an interesting time for acupuncture practitioners. During an era where we are able to gain the clearest view yet of the beneficial physiological reactions to acupuncture, the reactions of certain groups to this evidence is not always well received. With the growing volume of current scientific research to support the efficacy of acupuncture, one would think that greater acceptance in the greater scientific and medical communities would naturally follow.
Yet with the gold standard of clinical research defined by trials initially designed to test the effectiveness of pharmaceuticals against an inert placebo, true results can easily be skewed and the efficacy of acupuncture can be made to appear minimal. Until such time that trials make use of a more effective placebo to compare acupuncture to, other than say… actual acupuncture (sham acupuncture uses needles placed in areas of the body not related to the illness, yet still elicits a positive physiological response), an accurate clinical standing of the magnitude of its effectiveness remains unclear.
The increasing amount of research that supports acupuncture for the treatment of a great number of diseases will only grow in volume over the coming years. Hopefully, just as acupuncture itself has evolved with the times, perhaps clinical trials can too by adopting a more pragmatic approach. However, despite the long journey it has endured, acupuncture still holds a place in the modern healthcare system even after thousands of years. All going well, it will survive a few more.
Kavoussi, B & Ross, B 2006, ‘The Neuroimmune Basis of Anti-inflammatory Acupuncture’, INTEGRATIVE CANCER THERAPIES, Vol. 6, No. 3, pp. 251-257, viewed 17 April 2017, http://www.chiro.org/acupuncture/FULL/Neuroimmune_Basis.pdf, p. 251
Kopf, A & Patel, N 2010, ‘Guide to Pain Management in Low-Resource Settings’, International Association for the Study of Pain, viewed 31 March 2017, http://www.uitbs.org.rs/materijal/2010_1115/Kopf_A.pdf#page=25, p. 13
Baldry, P 2005, Acupuncture, Trigger Points and Musculoskeletal Pain, 3rd Edition, Elselvier, pp. 46 – 47
Kopf & Patel loc.cit.
Lin, L, Skakavac, N, Lin, X, Lin, D, Borlongan, M, Borlongan, C & Cao, C 2016, ‘Acupuncture-Induced Analgesia: The Role of Microglial Inhibition’, Cell Transplantation, Vol. 25, pp. 621–628, viewed 21 April 2017, http://www.ingentaconnect.com/contentone/cog/ct/2016/00000025/00000004/art00003?crawler=true&mimetype=application/pdf, p. 621
Zhang, R, Lao, L, Ren, K & Berman, B 2014, ‘Mechanisms of Acupuncture-Electroacupuncture on Persistent Pain’, Anesthesiology, Vol. 120, pp. 482 – 503, viewed 21 April 2017, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3947586/
Wu, S, Leung, A & Yew, D 2016, ‘Acupuncture for Detoxification in Treatment of Opioid Addiction’, East Asian Arch Psychiatry, No. 26, pp. 70 – 76, www.ebsco.com, viewed 15 January 2017, p. 71
Lin et al. loc.cit. p. 622
Zhang et al. loc.cit.
Lin, J & Chen, W 2008, ‘Acupuncture Analgesia: A Review of Its Mechanisms of Actions’, The American Journal of Chinese Medicine, Vol. 36, No. 4, 635–645, viewed 21 April 2017, http://www.encognitive.com/files/Acupuncture%20Analgesia::%20A%20Review%20of%20Its%20Mechanisms%20of%20Actions.pdf, p. 640
Lin et al. loc.cit. p. 625
Lin & Chen loc.cit. p. 637
Loh, H, Tseng, L, Wei, E & Li 1976, ‘beta-endorphin is a potent analgesic agent’, Proceedings of the National Academy of Sciences of the United States of America, Vol. 73, No. 8, pp. 2895–2898, viewed 22 April 2017, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC430793/
Stanford University Medical Centre 1979, ‘Stanford University Medical Centre News Bureau’, Stanford Medicine Website’, viewed 20 April 2017, http://med.stanford.edu/content/dam/Timeline/legacy-1979_goldstein_A33.pdf
McDonald, J & Janz, S 2017, ‘The Acupuncture Evidence Project: Plain English Summary’, AACMA Website, viewed 21 April 2017, http://acupuncture.org.au/OURSERVICES/Publications/AcupunctureEvidenceProject.aspx, p. 2
Ibid, p. 1
Qaseem, A, Wilt, T, McLea, R, & Forciea, M 2017, ‘Noninvasive Treatments for Acute, Subacute, and Chronic Low Back Pain: A Clinical Practice Guideline From the American College of Physicians’, Annals of Internal Medicine, http://annals.org/aim/article/2603228, viewed 28 April 2017