The Ph.D. Defined
The Ph.D. is a doctoral degree, the highest graduate degree awarded in American universities. In the U.S., a Ph.D. program usually takes from four to eight years to complete.

M.D.-Ph.D. Programs
A number of medical schools offer combined M.D.-Ph.D. degree programs, which provide students the opportunity to earn both the M.D. and the Ph.D. in areas pertinent to medicine

Psychiatrists are doctors who specialize in the physical causes and effects of mental illness. Some focus on talk therapy, helping patients heal through talking about their problems, and others focus on treating illness with medication. Many combine these approaches.

Unlike psychoanalysts, who focus on the unconscious, psychiatrists who take a cognitive approach focus on the way their patients think about themselves and the world around them.

Many MDs do not feel comfortable dispensing prescriptions for psychotropic medications, and thus it's important to have a psychiatrist monitor and prescribe these for patients needing them.