Can't speak for GP, but generally I believe there is a not insignificant chance that the treatment I'm being provided by the doctor is ineffective or even count

Can't speak for GP, but generally I believe there is a not insignificant chance that the treatment I'm being provided by the doctor is ineffective or even counterproductive. I'll still generally follow the doctor's advice at least after doing a brief literature search to confirm that the doctor's advice is aligned with contemporary best practices. Part of science is acknowledging epistemic uncertainty yet still acting on imperfect information.