Nocebo effect occurs when something which is inert (innocuous) is invested with negative belief and then causes ill health, and some say, even death. There are many studies which have examined Nocebo effect. There is a Japanese study of schoolboys who had identified what they thought caused them allergy: lacquer tree leaf. They were blind folded and each arm was tested with alleged allergen and non-allergen (chestnut tree leaf). When their arms were touched with chestnut tree leaf but boys were told it was poisonous lacquer tree leaf within minutes 75% of the boys developed skin rash on that arm. The arm which was brushed with poisonous lacquer tree leaf was rash free when they were told it was chestnut leaf.
In Framingham study women who believed they were at the risk of heart disease had four times higher death rate than women who had similar cardiac risks but did not believe they were ill.
There are studies in asthma which confirm nocebo effect exists.
There are also anecdotal case studies of patients dying when told by doctors the prognosis was poor, with subsequent autopsy showing no evidence of eg metastasis and tumour size very small.
Most doctors would know little of Nocebo simply because it is unethical practice to frighten patients and cause them harm.
This does not mean that there are no doctors who would not give negative prognosis when induced by payments eg from unethical solicitors. But what happens if patients believe doctors giving such negative outlook?
There are people who make Voodoo dolls commercially. See the one on the right. Some are so funny they make me laugh.