How is delusional disorder diagnosed?

How is delusional disorder diagnosed?

Healthcare providers — mainly mental health professionals — diagnose delusional disorder when a person has one or more delusions for one month or more that can’t be explained by any other condition. The person must also not have the characteristic symptoms of other psychotic disorders, such as schizophrenia.

If someone is experiencing signs and symptoms of delusional disorder, a healthcare provider will perform a complete medical history and physical examination. Although there aren’t any laboratory tests to diagnose delusional disorder, their healthcare provider might use various diagnostic tests — such as imaging tests, a urine drug screen and blood tests — to rule out any physical conditions, medications or substances that could be causing the symptoms.

If their healthcare provider finds no physical reason for the symptoms, a consultation with a psychiatrist or psychologist will likely be made. Psychiatrists and psychologists use specially designed interview and assessment tools to evaluate a person for a psychotic disorder. They’ll ask questions about the delusions and assess the person’s mental status.

The psychiatrist or psychologist may also interview family members and friends so they can provide further details about the person’s delusions and a timeline of the symptoms.

As other mental health conditions can cause delusions, mental health professionals carefully assess the person for other symptoms. Delusional disorder can be misdiagnosed as any of the following conditions:

• Obsessive-compulsive disorder.
• Schizophrenia.
• Delirium/major neurocognitive disorder.
• Bipolar disorder.
• Personality disorders, especially borderline personality disorder and paranoid personality disorder.