Delusional disorder is an uncommon psychiatric condition in which the patients present with delusions, but with no accompanying prominent hallucinations, thought disorder, mood disorder, or significant flattening of affect. Delusions are a specific symptom of psychosis. Non-bizarre delusions are fixed false beliefs that involve situations that could potentially occur in real life; examples include being followed or poisoned. Apart from their delusions, people with delusional disorder may continue to socialize and function in a normal manner and their behaviour does not generally seem odd or bizarre. However, the preoccupation with delusional ideas can be disruptive to their overall lives. For the diagnosis to be made, auditory and visual hallucinations cannot be prominent, though olfactory or tactile hallucinations related to the content of the delusion may be present. To be diagnosed with delusional disorder, the delusion or delusions cannot be due to the effects of a drug, medication, or general medical condition, and delusional disorder cannot be diagnosed in an individual previously properly diagnosed with schizophrenia. A person with delusional disorder may be high functioning in daily life, and this disorder bears no relation to one's IQ.Winokur, G. (1977). Delusional Disorder (Paranoia). Comprehensive Psychiatry, 18(6), 513. Retrieved March 17, 2012, from According to German psychiatrist Emil Kraepelin, patients with delusional disorder remain coherent, sensible and reasonable. The Diagnostic and Statistical Manual of Mental Disorders (DSM) defines six subtypes of the disorder characterized as erotomanic (believes that someone is in love with him or her), grandiose (believes that s/he is the greatest, strongest, fastest, richest, and/or most intelligent person ever), jealous (believes that the love partner is cheating on him/her), persecutory (delusions that the person or someone to whom the person is close is being malevolently treated in some way), somatic (believes that he/she has a disease or medical condition), and mixed, i.e., having features of more than one subtype. Delusions also occur as symptoms of many other mental disorders, especially the other psychotic disorders. The DSM-IV, and psychologists, generally agree that personal beliefs should be evaluated with great respect to cultural and religious differences, since some cultures have widely accepted beliefs that may be considered delusional in other cultures.
