We often hear of the placebo effect in Parkinson's. Usually it is seen as a problem, because it makes it difficult to interpret the results of clinical trials. I see it differently. Placebos could be used as therapies in their own right, after all clinical trial after clinical trial has found that they work, reducing the symptoms of PD. We could even engineer them to maximise their effectiveness. And if they lose their effectiveness over time, there's an infinite number of new placebos to move to.