What is the difference between a Psychologist, Psychiatrist and a Counselor?

Psychologists may work in a variety of settings, including private practice, schools, mental health clinics and hospitals. Many doctoral-level psychologists conduct scientific research. To practice as a clinical psychologist, you need a Ph.D. in psychology, or a Psy.D, or Doctor of Psychology, and a state license to practice. Those wanting to prescribe medication in the above-mentioned states have to undergo additional training.