So, dopamine deficiency is not the whole story with PD: serotonin plays a part too.

"The researchers found that in pre-symptomatic people with a hereditary risk of Parkinson's there was a loss of serotonin in several areas of the brain that are known to be affected in Parkinson's. Therefore this could be a change that happens in the early stages of Parkinson's."

The thing I can't understand is why this research isn't translated into a simple serotonin based therapy. The same goes for the other neurotransmitters.

John