According to Jacob Stegenga, a Cambridge lecturer in philosophy of science, and author of the recent book, ‘Medical Nihilism’, many pharmaceutical interventions have a thin theoretical and evidentiary basis. He discusses this with David, including how pharmaceutical companies can manipulate science, especially controlled trials, to get their drugs approved, even if they are useless or worse.
For more information on Jacob Stegenga and ‘Medical Nihilism’, see: https://www.people.hps.cam.ac.uk/index/teaching-officers/stegenga