The roles of expectation and dopamine in the placebo effect in Parkinson's Disease

The placebo effect, when a patient’s beliefs or expectations can influence the course and outcome of disease, is a well-recognized medical phenomenon that is particularly prominent in neurological disorders such as depression, pain and Parkinson’s Disease. But little research to date has examined the therapeutic impact of taking placebos and the mechanism by which they work. Studying the placebo effect is also important to assess the need to control the phenomenon in clinical trials, and to address the difficulty in detecting a true therapeutic effect when benefits are masked by a strong placebo effect. Sarah Lidstone is using advanced imaging techniques to assess the physiological changes in the brain associated with the placebo effect in Parkinson’s Disease. Sarah is studying how a patient’s expectation about their treatment influences how they respond to that treatment. Her group has already discovered that a placebo can induce the release of dopamine in the brains of Parkinson’s patients. A deficiency of dopamine, a chemical that transmits messages between brain cells involved in controlling movement, causes Parkinson’s Disease. The research could help explain how the placebo effect occurs in Parkinson’s, and improve treatment for the disease, along with drug addiction, depression and pain.