Psychiatrists actually go through 4 years of medical school to become practicing physicians, and then go through more years of school to learn about mental disorders. They understand the physical (brain or other organ) reasons for mental illness and prescribe medications for them. Mostly, they do not do counseling, except to find out what the problem is and the symptoms you are experiencing.. . A psychologist goes through regular college, and then may or may not have an advanced degree - a PhD in psychology may take another 4 years of college. It is all based in the mental/sociological causes of disturbances. They provide counseling, not medications. In general, they cost much less than a psyciatrist would.