Both psychiatrists and psychologists conduct psychotherapy and research, but there are two significant differences between the two professions.
The number one difference is in education. A psychiatrist has a medical degree and is a medical doctor, whereas a psychologist has a Master's or Doctoral Degree in Psychology. The second difference is that a psychiatrist can prescribe medication, whereas a psychologist cannot.
When considering this career, ask yourself whether you'd prefer to assess, diagnose, treat mental illness, and prescribe medication (psychiatrist), or if you would rather conduct psychotherapy, administer psychological tests, and conduct research (a psychologist).