Some will remember the Andy Griffith Show where Emma Watson was taking her pill for her aches and pain. The pharmacist, Ellie Walker, was conflicted about refilling her prescription with a placebo. Emma simply could not live without her pill. In a clinical trial some get a real drug and others get a placebo. There can be a placebo effect on individuals taking the real drug. This means that the placebo effect can be beneficial to the results for the real drug. If you believe a medical treatment will have a positive effect then you are more likely to have that experience.
The nocebo is just the opposite. A harmless substance creates a negative effect. If you are uncomfortable with a medical treatment, the inability to embrace it could be a problem. What if a physician prescribes a statin drug for elevated cholesterol, which you do not want? Every time you swallow you have a negative feeling. The results can be about one’s expectations.