In the same way that your family doctor can prescribe medications to help patients with high blood pressure or thyroid problems, psychiatrists can prescribe a number of medications that are effective against mental illnesses such as depression, manic-depression, panic disorder, anxiety disorders, obsessive-compulsive disorder and schizophrenia. Psychiatrists use medications when thorough evaluation of a patient suggests that medication may correct imbalances in brain chemistry that are thought to be involved in some mental disorders. Psychiatrists may use medications in combination with psychotherapy.