A psychologist is trained to provide professional counseling on psychological and emotional issues and may also specialize in areas such as marital counseling, relaxation therapy, stress management, or sex therapy. A psychologist does not have the ability to prescribe medications.  A neurosurgeon is doctor who specializes in surgery on the brain, spine, and other parts of the nervous system. Lastly, a neurologist is a physician who diagnoses and treats disorders of the nervous system.