I discussed this with my neurologist yesterday because I was concerned that my propensity to develop Parkinsonism on some antipsychotics might mean that I am more prone to developing Parkinson's later in life. I also carry one gene mutation of Parkinson's. The neurologist said that the mutation I carry only slightly elevates the risk, which reassured me. He also explained the difference between Parkinsonism, a side effect of antipsychotics, and true Parkinson's. It is now possible to distinguish between the two. In my case, it is not a necessary line of investigation because Parkinsonism instantly resolves if I discontinue the offending agent.

It is established that antipsychotics do not cause Parkinson's. They can cause Parkinsonism and often do but they do not cause true Parkinson's. Parkinsonism does not make Parkinson's more likely. Long term intake of antipsychotics does not increase the risk of Parkinson's.

He also told me that Parkinson's is not an especially heritable disorder.