Dr. A. Jon Stoessl is Professor of Medicine (Neurology) and Director of Pacific Parkinson's Research Centre at the University of British Columbia in Vancouver. A native of London, UK, Stoessl moved to Canada in 1960 and obtained his MD from the University of Western Ontario in 1979. His post-doctoral work focused on movement disorders, PET technology, Alzheimer's disease and neuropharmacology. Stoessl's current research is focussed on understanding basal ganglia disorders, particularly Parkinson's disease, including complications of long-term therapy. Stoessl's lab uses positron emission tomography (PET) to study the natural history and progression of Parkinson' s disease, compensatory changes that take place during the course of the disease, and changes associated with the development of motor complications. Stoessl and his colleagues have used PET to demonstrate dopamine release as a mechanism underlying the placebo effect in Parkinson's. His lab is now interested in the application of PET to study gene expression. These studies are supported by the Canadian Institutes of Health Research.

Shane Roche asks:
What if you told your patients that they were receiving the placebo, but in fact were getting medicine? Did you find that the same results were seen?

Shane Roche, age 10

Stoessl's response:
Good question, Shane.

We did not do the test exactly that way - we gave every patient 4 injections and told them that one of them would be inactive (placebo), and that the others would be active medication - obviously, we did not tell people which injection would be the placebo.

If you give somebody only a single injection and tell them it is placebo, when it is actually active medication, that adds another ethical problem - because all medications have potential side effects, you need to warn people about these - so, it wouldn't be fair to tell people they aren't getting anything when in fact they are, because you could be subjecting them to a (low) risk. But if you did do this, you might actually expect that the effects of active medication would not be as great as they are when people think they are getting the real thing - because their level of expectation is lower

Ruth asks:
Have you published results of your study profiled on Scientific American Frontiers (Parkinsons and placebos)? If so, where? How can I get more information on this subject?

Stoessl's response:
These are the papers we have published on the placebo effect. The original one is #1, and a very interesting followup (based on further analysis of the same data) is #4. The others are review articles.

1. de la Fuente-Fernandez R, Ruth TJ, Sossi V, Schulzer M, Calne DB, Stoessl AJ (2001). Expectation and Dopamine Release: Mechanism of the Placebo Effect in Parkinson‚s Disease. Science 293: 1164-1166.

2. de la Fuente-Fernandez R, Schulzer M, Stoessl AJ (2002). The placebo effect in neurological disorders. Lancet Neurology 1: 85-91.

3. de la Fuente-Fernandez R, Stoessl AJ (2002). The placebo effect in Parkinson‚s disease. Trends in Neurosciences 25: 302-306.

4. de la Fuente-Fernandez R, Phillips AG, Zamburlini M, Sossi V, Calne DB, Ruth TJ, Stoessl AJ (2002). Dopamine release in human ventral striatum and expectation of reward. Behav. Brain Res. 136:359-63.

5. de la Fuente-Fernandez R, Stoessl AJ (2002). The biochemical bases for reward: implications for the placebo effect. Evaluation and the Health Professions 25:387-98.

You might also be interested in this paper, from the group in Turin who were working on expectation and pain:

A. Pollo, E. Torre, L. Lopiano, M. Rizzone, M. Lanotte, A. Cavanna, B. Bergamasco, and F. Benedetti. Expectation modulates the response to subthalamic nucleus stimulation in Parkinsonian patients. NeuroReport 13 (11):1383-1386, 2002.

Hope this helps.