To diagnose a psychotic disorder, doctors will talk to the person, give them a checkup, and consider whether something else might be to blame for the symptoms. The person may get blood tests and brain imaging (such as MRI scans) to rule out physical illness or drug use like cocaine or LSD. If the doctor finds no physical reason for the symptoms, he or she may refer the person to a psychiatrist or psychologist. These mental health professionals will use specially designed interview and assessment tools to decide whether the person has a psychotic disorder.