Psychiatrist: This medically-focused career path is one for those interested in the study, treatment, and prevention of mental disorders. Psychiatrists are required to carry and M.D. or D.O. degree, so this is definitely not an entry-level position. However, it is a hugely rewarding path which allows practitioners to help those suffering from everything ranging from substance abuse to ADHD. It differs from a psychologist in that psychiatrists can prescribe medication.