Psychiatry is the branch of medicine that deals with mental health, or how people think, feel, and behave. Unfortunately, psychiatry has caused a lot of controversy, or disagreement, over the years. Some people worry that psychiatrists don't really understand mental illness, and believe that the medicines they give people can actually do more harm than good. Other people worry that psychiatry is used to stigmatize people who are seen as "different", or not following the same rules as everyone else.