A person will answer questions about their physical and psychiatric history and possibly also get a physical exam.
There are no lab tests that specifically diagnose this disorders. Doctors may use tools such as brain imaging (including MRI scans) and blood tests to rule out other causes.
If a doctor finds no physical reason for the symptoms, he or she might refer the person to a psychiatrist or psychologist. These mental health experts will talk to the person, listen to their symptoms, observe their behavior, and find out if the person is close to someone who is known to have delusions.