Scientists discover chemical link that may explain the 'placebo
effect'
By Steve Connor, Science Editor
Published: 30 January 2006

Scientists may have discovered a possible cause of the "placebo
effect", where a sham medical treatment results in a genuine benefit
to the patient. A study has found production of a
chemical "messenger" in the brain appears to play a critical role.

Jon Stoessl, professor of neurology at the University of British
Columbia in Vancouver, believes the placebo effect could be caused by
the production of a chemical in the brain called dopamine, which is
involved in triggering the expectation of pleasure and reward.

Professor Stoessl carried out a study on patients suffering from
Parkinson's disease, which is known to result from a lowering of
normal levels of dopamine.

Normally when Parkinson's patients are given a chemical precursor to
dopamine they show an improvement in levels of dopamine produced
naturally, which makes them feel better. But when Professor Stoessl
injected six of his patients with a simple saline solution he found
that they too showed an improvement in levels of dopamine - the
average increase was more than double.

The patients given the saline solution were told they were to be
given the actual treatment and as a result they were expecting to
feel an improvement, Professor Stoessl said.

Details will be shown in Alternative Medicine: the evidence at 9pm on
BBC2 tomorrow.

Scientists may have discovered a possible cause of the "placebo
effect", where a sham medical treatment results in a genuine benefit
to the patient. A study has found production of a
chemical "messenger" in the brain appears to play a critical role.

Jon Stoessl, professor of neurology at the University of British
Columbia in Vancouver, believes the placebo effect could be caused by
the production of a chemical in the brain called dopamine, which is
involved in triggering the expectation of pleasure and reward.

Professor Stoessl carried out a study on patients suffering from
Parkinson's disease, which is known to result from a lowering of
normal levels of dopamine.

Normally when Parkinson's patients are given a chemical precursor to
dopamine they show an improvement in levels of dopamine produced
naturally, which makes them feel better. But when Professor Stoessl
injected six of his patients with a simple saline solution he found
that they too showed an improvement in levels of dopamine - the
average increase was more than double.

The patients given the saline solution were told they were to be
given the actual treatment and as a result they were expecting to
feel an improvement, Professor Stoessl said.

Details will be shown in Alternative Medicine: the evidence at 9pm on
BBC2 tomorrow.

<http://news.independent.co.uk/world/science_technology/article341940.
ece>