A new medication for schizophrenia appears to work because it blocks dopamine from binding to a receptor. the new medication functions as:

A new medication for schizophrenia appears to work because it blocks dopamine from binding to a receptor. The new medication functions as dopamine antagonist.

This is because it prevents it from doing what it is supposed to do naturally, and it acts just an antagonist would in a novel, while trying to thwart the protagonist's plans. It cannot be a dopamine production inhibitor because dopamine is still produced - it is just not allowed to bind to a receptor.