What Is It? Delusional disorder is classified as a psychotic
disorder, a disorder where a person has trouble recognizing
reality. A delusion is a false belief that is based on an
incorrect interpretation of reality. Delusions, like all
psychotic symptoms, can occur as part of many different
psychiatric disorders. But the term delusional disorder is used
when delusions are the most prominent symptom. A person with
this illness holds a false belief firmly, despite clear evidence
or proof to the contrary. In delusional disorder, the delusions
involve circumstances that could occur in reality even though
they are unlikely (for example, the family next door plotting to
kill you). Sometimes delusions are considered "bizarre" (for
example, feeling controlled by an outside force or having
thoughts inserted into your head) and such delusions may be more
common in schizophrenia. A religious or cultural belief that is
accepted by other members of the person's community is not a
delusion. There are several types of delus