Delusion means having a firm belief in something that does not exist or does not have any probability of happening. There are some people who are aware that they are having delusions. They imagine a type of life that is different from their own.
There are also some who are having some psychological issues who may not be able to distinguish what is real from what is not real. This is revealed to be a possible symptom of a mental disorder. A person who is having delusions is required to be checked soon so that the main reason for this will be addressed and if possible, be cured.