To what extent is their improved mental health a placebo effect from being convinced that they “finally have the answers” and getting dopamine from the process

To what extent is their improved mental health a placebo effect from being convinced that they “finally have the answers” and getting dopamine from the process of successfully converting people to carnivore diets tho? Mikhaila Peterson, for instance, insists that it’s the carnivore diet that cured her depression — when IMO it’s equally possible that the positive social feedback she gets from toting a depression cure is what actually cured her depression.