This is more or less the basis of a lot of western esotericism and ceremonial magick. Consider it a weaponization of the placebo effect, or the closest thing to creatio ex nihilo one can personally experience. Dialogue with the purveyor of negative self-talk is another modality in this space.
The coolest thing about the placebo effect is that it works even if you know it’s a placebo so the more you believe in science the more you can pick some random bs and be like “This will help me because I think it will, and the placebo effect is real” And it will actually. fkn. work.