China is running seven clinical trials using chemogenetics, a technique that lets doctors control specific neurons with designer drugs, but the current approach uses clozapine at ultra-low doses instead of truly inert compounds, raising questions about precision and safety. The technology is sound for treating epilepsy and Parkinson's disease, though next-generation versions could be significantly better.

• Seven ongoing trials in China are testing chemogenetics for epilepsy, Parkinson's disease, and pain by injecting modified genes into the brain that make neurons respond to clozapine taken orally—affecting roughly 10 patients so far.
• Clozapine is used at 1% of the antipsychotic dose in Parkinson's trials and similarly low in epilepsy trials, minimizing off-target effects, but it's still not truly inert and requires long-term monitoring for rare idiosyncratic reactions like agranulocytosis.
• Current trials use hM4Di, which is only 2 amino acids different from the native human M4 receptor, reducing immune rejection risk, but genuinely inert alternatives like DCZ exist and could improve precision in future versions—they just haven't been approved for human use yet.