Delusional disorder

Delusional disorder is a mental disorder in which a person has delusions, but with no accompanying prominent hallucinations, thought disorder, mood disorder, or significant flattening of affect. Delusions are a specific symptom of psychosis. Delusions can be bizarre or non-bizarre in content; non-bizarre delusions are fixed false beliefs that involve situations that could occur in real life, such as being harmed or poisoned. Apart from their delusion or delusions, people with delusional disorder may continue to socialize and function in a normal manner and their behavior may not necessarily seem odd. 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. The 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 as measured, for example, by the Global Assessment of Functioning. Recent and comprehensive meta-analyses of scientific studies point to an association with a deterioration in aspects of IQ in psychotic patients, in particular, perceptual reasoning, although the between-group differences were small. 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: erotomanic (belief that someone is in love with one), grandiose (belief that one is the greatest, strongest, fastest, richest, or most intelligent person ever), jealous (belief that one is being cheated on), persecutory (delusions that one or more people are treating the person with the disorder in a malevolent or harmful way), somatic (belief that one...