Has anyone studied whether there is an opposite anti-placebo effect? Like if a patient lacks confidence in their doctor and doesn't believe that a real medicine will actually work, is it less likely to be effective?
> A nocebo effect is said to occur when negative expectations of the patient regarding a treatment cause the treatment to have a more negative effect than it otherwise would have.
People with [psycho]somatic symptom disorders, with medically unexplained symptoms, are more likely to report negative side effects in response to placebo, for example.
When I've read about it, the research is often focused on perceived negative symptoms rather than lack of therapeutic effect, but that's just my impression and I suspect both happen.