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.
No. Mental illness, or psychiatric disability, has to do with emotional or behavioral problems. While children with mental retardation can have a psychiatric disability, the two conditions are separate and require different types of intervention.