Learn English – Word for thinking something is happening when it’s not

expressionsphrase-requestspsychologysingle-word-requestsword-choice

Is there a word for the psychological effect of thinking that something is happening and thus feeling the effects of that thing yet nothing is really happening?

An example would be when you get falsely diagnosed with some sort of illness and feel the effects of this illness even though you don't actually have the illness.

I was thinking of calling it "placebo effect", but I think that applies only to being given "medicines" that don't do anything and you feel better due to the way your brain works.

Best Answer

Feeling imaginary symptoms is a kind of delusion.

Macmillan:

delusion
NOUN
2 [UNCOUNTABLE] MEDICAL a mental condition in which you believe things that are not true