One of the classic ways an abuser controls their prey is to manipulate the environment so that the abused individual begins doubting their own observations regardless of what is occurring in front of them.
In the 1944 movie, Gaslight, this was accomplished by the villainous husband (played by Charles Boyer) adjusting the intake to gas-powered lights (causing them to flicker) and simultaneously denying that any change was occurring to his mentally abused wife (played by Ingrid Bergman). The term gaslighting originated from this classic movie.
In modern times, this is accomplished by having medical providers all echo the same message that a patient’s injury has nothing to do with the pharmaceutical (or other medical procedure in question). Most commonly, it instead is argued that the symptoms they are experiencing are due to pre-existing psychiatric issues the patient has (e.g., anxiety), which are treated with medications that often create additional issues.
Before we go any further, I want to emphasize just how miserable this is to go through as an injured patient. Imagine what it would be like if (due to the medical injury) the world you had previously known collapsed around you and every single person you trusted (including your friends and family who defer to the judgment of “experts”) told you that it was all in your head and you just needed psychiatric help. It’s a perfect recipe for going insane.