IDEAS OF REFERENCE are overvalue
d ideas in which the patient is virtually, but not totally
, convinced that objects, people, or events in his immediate environment have personal significance for him. For example, whenever a man sees a red car parked in front of his house, he is convinced that it is a "message" from the FBI warning him to be on the alert for drug addicts.
These are similar to delusions, but vary in belief solidity: a delusion is a false belief about external reality that is firmly maintained despite contrary evidence or proof.