John Wilkes Booth was the son of prominent, wealthy actors. He, too, became an actor and was so popular, he was one of the first to have his clothes ripped off by fans. Hulton Archive/Getty hide caption
Psychology is the systematic investigation of the human mind, including behavior and cognition. It thus encompasses both normal and abnormal behavior. On the other hand, psychiatry is a branch of medicine dealing with mental illness.
The test can be used when a patient is first assessed, and later in the course of treatment to see how well the patient is responding to medication. A cognitive evaluation can also be used to determine whether or not a patient is experiencing any problems as a side effect of psychiatric medication.