A better understanding of the brain mechanisms behind the placebo effect may help clinicians maximize people's health beyond the power of positive thinking, according to an article published in the journal Brain. The placebo effect is a beneficial health outcome resulting from a person's anticipation that an intervention—pill, procedure, or injection, for example—will help them. A clinician's style in interacting with patients also may bring about a positive response that is independent of any specific treatment.
This review of the scientific literature, funded in part by NCCAM, looked at the implications of the placebo effect in clinical trials. In addition, the review also identified how the body's central nervous system is intricately involved in the placebo response. Specific placebo studies were addressed with a focus on particular disorders including pain, Parkinson's disease, multiple sclerosis, epilepsy, and aging/dementia. Key findings from the review included:
- For some interventions, outcomes may be influenced as much by the patient's expectations as by the intervention itself. A sugar pill may have a stronger or weaker effect based solely on its color, its size, or if it is given in tablet rather than pill form.
- Expectations may be related to culture, previous interactions with the clinical setting, verbal communication, conditioning, or a combination of factors.
- Several of the brain's neurotransmitter systems, such as opiate and dopamine, are involved in the placebo effect. In addition, neuroimagery techniques have shown activity in specific regions of the brain after administration of a placebo.
- Pain is particularly responsive to the placebo effect.
The author concluded that a better understanding of how the placebo effect works can benefit clinical trial design and interpretation of results, as well as efforts to improve people's health.
Oken BS. Placebo effects: clinical aspects and neurobiology. Brain.; 131(11):2812–2823.2008