Clinical psychologist is to psychiatrist as "Ph.D" is to "M.D".
Clinical psychologists must have a doctoral qualification in psychology. There are two doctoral-level psychology degrees - the Ph.D., or specialist in psychology, which has a tendency to be more research-based, and the Psy.D., or specialist of psychology, which concentrates more on clinical work, for example, psychotherapy.
Psychiatrists need to acquire a medical degree - either a M.D., or Doctor of Medicine, or a D.O., or Doctor of Osteopathy. In the wake of finishing therapeutic school, specialists must get a state permit to endorse prescription.