Delusion is a disorder and uncommon psychiatric condition. It may arise from a pre-existing paranoid personality disorder in which patients present with circumscribed symptoms. Delusion is of different types such as Grandiose Type, Jealous Type and Somatic Type. Delusions are also associated with a wide range of non-psychiatric medical conditions. Biological factors may play some role in the development of delusions. Patients with neurologic disorders are most commonly associated with delusions. The cause of delusions has been linked to various risk factors which include genetic factors, environmental factors and psychological factors. When delusion disorders occur late in life, they suggest a hereditary pre-disposition.

The signs and symptoms of delusion may include feeling exploited, bearing grudges for a long time, responding readily to perceived slights, an irritable and angry mood, hallucinations etc. The main symptom is a persistent delusion or a fixed belief about a situation that is not happening. In Grandiose Type, there is delusion that the person has a special power or ability with a powerful person or figure. In Jealous Type, there is delusion that a sexual partner is being unfaithful. In Somatic Type, there is delusion of having a physical illness.

Common treatment of delusion includes medication and psychotherapy. Psychotherapy is the primary treatment and it can help with the behavioral and psychological problems associated with delusion disorder. Individual psychotherapy can help the person recognize and correct the underlying thinking that has become distorted. Family therapy can help families deal more effectively with a loved one who has delusions.