Placebo studies
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Placebo studies is an interdisciplinary academic discipline concerning the study of the placebo effect. Clinical placebo studies suggest that expectation effects may play a significant role; one specific case being the clinical trials of major depressive disorder (MDD).[1] Alongside major depressive disorder, placebos have been argued to produce clinical improvement in the management of pain, Parkinson's disease, and some immunological disorders.[2][3]
Background[edit]
The idea of a "placebo effect" in modern parlance can be traced to aninfluential 1955 study entitled The Powerful Placebo firmly established the idea that placebo effects were clinically important,[4] and were a result of the brain's role in physical health. Concepts such as regression to the mean were not accounted for, and reassessments of the source data have found no evidence of any placebo effect.[5][6] Subsequent research has found that placebos have no impact on diseases;[7][8] they can only affect the person's perception of their own condition.[8] Improvements that patients experience after being treated with a placebo can also be due to unrelated factors, such as a natural recovery from the illness.[8]
Initial clinical experiments[edit]
In 1954, at Harvard Medical School a team led by Louis Lasagna lead the first known experiment to detect placebo responders.[9] In this experiment approximately 162 postoperative patients were observed for significant pain relief from subcutaneous injections of placebo and morphine.[9] Differences in response and attitude were exhibited between placebo respondents and non-placebo respondents.[9] "Using Rorschach tests and qualitative interviews, respondents, compared to non-respondents, were more anxious, self-centered, viewed the hospital care as 'wonderful', had more somatic symptoms, used more cathartics, were 'talkers and were regular church goers.".[10]
In 1957, a team led by Wolf at Cornell University Medical School conducted an experiment to determine the reliability of the placebo response within the placebo study.[11] The conclusion produced the answer to be "the likelihood of predicting placebo responses was not enhanced by increasing the number of placebo tests performed on any individual."[11]
A study on placebo effects from omega 3 fatty acids and their persistent climb was done in 2006. This study concluded that although the results were "too premature to evaluate," they showed there was a relationship between the efficacy of the antidepressant placebos and the intake of omega threes PUFAs.[12]
Studies on the role of placebos in Parkinson's disease have provided insight into the neurobiological mechanisms by which a placebo acts. Placebos have been found to improve motor control symptoms in individuals with Parkison's disease by causing the brain to release dopamine. Furthermore, the size of the effect depends on the patient's expectation of improvement, and larger dopamine release can be conditioned through prior exposure.[2]
Further reading[edit]
- Colloca, Luana. Neurobiology of the placebo effect. Part I. Cambridge, MA. ISBN 9780128143261. OCLC 1032303151. Search this book on
- Colloca, Luana. Neurobiology of the placebo effect. Part II (1st ed.). Cambridge, MA, United States. ISBN 9780128154175. OCLC 1049800273. Search this book on
References[edit]
- ↑ Brunoni AR, Lopes M, Kaptchuk TJ, Fregni F (2009). "Placebo response of non-pharmacological and pharmacological trials in major depression: a systematic review and meta-analysis". PLOS One. 4 (3): e4824. doi:10.1371/journal.pone.0004824. PMC 2653635. PMID 19293925.
- ↑ 2.0 2.1 Quattrone, Aldo; Barbagallo, Gaetano; Cerasa, Antonio; Stoessl, A. Jon (August 2018). "Neurobiology of placebo effect in Parkinson's disease: What we have learned and where we are going". Movement Disorders: Official Journal of the Movement Disorder Society. 33 (8): 1213–1227. doi:10.1002/mds.27438. ISSN 1531-8257. PMID 30230624.
- ↑ Pacheco-López, Gustavo; Engler, Harald; Niemi, Maj-Britt; Schedlowski, Manfred (September 2006). "Expectations and associations that heal: Immunomodulatory placebo effects and its neurobiology". Brain, Behavior, and Immunity. 20 (5): 430–446. doi:10.1016/j.bbi.2006.05.003. ISSN 0889-1591. PMID 16887325.
- ↑ Hróbjartsson A, Gøtzsche PC (May 2001). "Is the placebo powerless? An analysis of clinical trials comparing placebo with no treatment". The New England Journal of Medicine. 344 (21): 1594–602. doi:10.1056/NEJM200105243442106. PMID 11372012.
- ↑ Kienle GS, Kiene H (December 1997). "The powerful placebo effect: fact or fiction?". Journal of Clinical Epidemiology. 50 (12): 1311–8. doi:10.1016/s0895-4356(97)00203-5. PMID 9449934.
- ↑ Hróbjartsson A, Gøtzsche PC (August 2004). "Is the placebo powerless? Update of a systematic review with 52 new randomized trials comparing placebo with no treatment". Journal of Internal Medicine. 256 (2): 91–100. doi:10.1111/j.1365-2796.2004.01355.x. PMID 15257721. Gøtzsche's biographical article has further references related to this work.
- ↑ Hróbjartsson A, Gøtzsche PC (January 2010). Hróbjartsson A, ed. "Placebo interventions for all clinical conditions" (PDF). The Cochrane Database of Systematic Reviews. 106 (1): CD003974. doi:10.1002/14651858.CD003974.pub3. PMID 20091554.
- ↑ 8.0 8.1 8.2 "Placebo Effect". American Cancer Society. 10 April 2015.
- ↑ 9.0 9.1 9.2 Lasagna L, Mosteller F, Von Felsinger JM, Beecher HK (June 1954). "A study of the placebo response". The American Journal of Medicine. 16 (6): 770–9. doi:10.1016/0002-9343(54)90441-6. PMID 13158365.
- ↑ Kaptchuk TJ, Kelley JM, Deykin A, Wayne PM, Lasagna LC, Epstein IO, Kirsch I, Wechsler ME (July 2008). "Do "placebo responders" exist?". Contemporary Clinical Trials. 29 (4): 587–95. doi:10.1016/j.cct.2008.02.002. PMID 18378192.
- ↑ 11.0 11.1 Wolf S, Doering CR, Clark ML, Hagans JA (June 1957). "Chance distribution and placebo reactor". The Journal of Laboratory and Clinical Medicine. 49 (6): 837–41. PMID 13429202.
- ↑ Lin, Pao-Yen; Su, Kuan-Pin (2007-07-15). "A Meta-Analytic Review of Double-Blind, Placebo-Controlled Trials of Antidepressant Efficacy of Omega-3 Fatty Acids". The Journal of Clinical Psychiatry. 68 (7): 1056–1061. doi:10.4088/jcp.v68n0712. ISSN 0160-6689.
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