On: Parkinson's patient able to walk 6km without probl...

[maxerickson]

Nuplazid, an antipsychotic marketed for Parkinson's, targets the imbalance created by the massive loss of dopermergenic cells.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6007714/

It certainly had a significant impact on a Parkinson's patient I knew (from regular expressions of and involvement with delusional hallucinations to relatively normal, organized behavior).

Of course the loss of cells might be self reinforcing.