The placebo effect is a puzzling phenomenon. Placebos (sugar pills or saline solutions secretly substituted for actual drugs) are commonly used in clinical trials to set a baseline against which to measure the effects of a drug. However, people in the placebo group will often show improvements alongside the treatment group. The fact that an inactive substance, such as a sugar pill, can lead to faster recovery or decreased pain prompts us to consider the role that mindset and psychology play in response to treatments. A recent study by scientists at Northwestern University found that people respond differently to placebo treatments, and that this may depend on brain structure and psychological traits.
The study analyzed 63 patients with chronic back pain that were randomized into two different groups – one group received no treatment, and the other received a placebo pill containing lactose. Using MRI and fMRI scans, they found that a patient’s tendency to respond to placebo was mildly correlated with greater volume of the right subcortical limbic structures (involved in emotion, reward and memory formation) and decreased thickness of the right superior frontal gyrus (involved in self-awareness). The researchers also used questionnaires to assess personality traits. They found that the patients who reacted most positively to placebos had greater openness to experience and emotional awareness, and were less distracted by pain and discomfort.
Continuing to investigate the biological effects of placebos will greatly benefit patients. Prescribing inert drugs would allow patients to avoid the side effects and addictive properties associated with some prescribed drugs, while still gaining marginal benefits. Additionally, prescribing sugar pills could result in dramatic reductions in health care costs.
Managing Correspondent: Jeremy Gungabeesoon
Original Article: Brain and psychological determinants of placebo pill response in chronic pain patients. Nature Communications
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