The simplest answer lies in the educational background required for each profession. A psychiatrist has a degree in medicine and a psychologist has a doctoral-level degree in psychology. However, there are a number of other distinctions that make each profession quite unique.
Psychologists receive graduate training in psychology and pursue either a Ph.D. (Doctor of Philosophy) or Psy.D. (Doctor of Psychology) in clinical or counseling psychology. Doctorate programs typically take five to seven years to complete and most states require an additional one or two year long internship in order to gain licensure.