A fairly cautious article here on current work to stimulate the production of dopamine in Parkinson's patients: "Macaque monkeys that received gene therapy for symptoms of Parkinson's disease saw a significant improvement in their motor function without the side effects associated with current standard therapy ... For the past 40 or so years, the treatment of choice for Parkinson's has been so-called dopamine replacement therapy, which uses drugs to increase dopamine levels in the brain. The approach helps, but because the infusion of dopamine takes place in fits and bursts, not continuously, people often develop involuntary movements. Scientists have thus been focused on finding ways to deliver dopamine to the brain more continuously. Simultaneous insertion of three genes allowed certain cells in the brain to take over production of the neurotransmitter dopamine. ... But even if this gene therapy approach were to someday produce good results in humans, it still would not solve many of the myriad other problems associated with Parkinson's. ... the gene therapy would be considered a treatment rather than a cure because it 'corrects only dopamine-related symptoms.' ... an early-phase clinical trial in humans is in progress. ... So far, six Parkinson's disease patients have been treated - no serious adverse events, encouraging results so far. [But] the study is not ended, so still no final results."