Imagine taking a pill with absolutely no active medication, yet somehow feeling better afterward. Sounds impossible, right? Surprisingly, this phenomenon is known as the placebo effect, where an individual’s symptoms may improve due to expectations and the context surrounding a treatment rather than its active ingredients (Wager and Atlas 2015). But can simply believing that a treatment will work actually produce biological changes, or is the improvement entirely psychological?
Although the placebo effect may sound like someone is simply imagining improvement, research suggests otherwise. Placebo responses involve changes in brain regions that process pain, emotions, and expectations. These reponses can also involve neurotransmitters such as dopamine and the brain’s naturally produced opioids, which contribute to pain regulation (Wager and Atlas 2015). This demonstrates how psychological expectations can influence chemical signalling in the nervous system, which highlights the relationship between psychology, chemistry, and biology
One paticularly intersting aspect of the placebo effect is its influence on pain perception. Benedetti et al. (2005) reviewed evidence showing that placebo-induced pain relief can involve activating the body’s endogenous opioid system. These natrually produced chemicals bind to the opiod recepors and influence how pain signals get processed by the nervous system (Benedetti et al. 2005). This connects to neuronal signalling, as changes in chemical communication between neurons can alter the perception of pain. Interestingly, this means that expecting relief can sometimes activate these biological pathways which are also involved in repsonses to pain relief medication.
However, this raises another question: does someone need to believe they are receiving real medication for the placebo effect to occur? Kaptchuk et al. (2010) invesitagted this through an experiment involving 80 patients with irritable bowel syndrome (IBS). The participants were divided into two groups: one received pills that were openly described as placebos, while the other received no treatment. After three weeks, participants receiving placebos reported significantly greater improvement in their symptoms (Kaptchuk et al. 2010). What makes this experiment particularly fascinating is that participants knew the pills contained no active medication, which suggests that placebo responses may involve more than simply believing a treatment is real.
Despite these findings, it is important to distinguish between experiencing symptom relief and actually treating an underlying disease. The study by Kaptchuk et al. (2010) primarily examined self-reported symptoms, meaning the results do not establish that placebos can cure IBS. Furthermore, placebo responses vary depending on the condition and treatment context (Wager and Atlas 2015).
The placebo effect demonstrates how closely psychological and physiological processes are connected. Through changes in neural activity and chemical signalling, expectations can influence how individuals experience physical symptoms. Although placebos cannot replace effective medical treatments, understanding their mechanisms may help researchers improve how treatments are delivered. Ultimately, the placebo effect can challenge the idea that healing is purely physical, revealing just how powerful the relationship between the brain and body can be.
References
Benedetti, Fabrizio, Helen S. Mayberg, Tor D. Wager, Christian S. Stohler, and Jon-Kar Zubieta. 2005. “Neurobiological Mechanisms of the Placebo Effect.” Journal of Neuroscience 25 (45): 10390–10402.https://doi.org/10.1523/JNEUROSCI.3458-05.2005
Kaptchuk, Ted J., et al. 2010. “Placebos without Deception: A Randomized Controlled Trial in Irritable Bowel Syndrome.” PLOS ONE 5 (12): e15591. https://doi.org/10.1371/journal.pone.0015591
Wager, Tor D., and Lauren Y. Atlas. 2015. “The Neuroscience of Placebo Effects: Connecting Context, Learning and Health.” Nature Reviews Neuroscience 16: 403–418. 10.1038/nrn3976
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