Psychotherapy is one way to treat psychological disorders. The other is biomedical therapy—physically changing the brain’s functioning by altering its chemistry with drugs; affecting its circuitry with electrical stimulation, magnetic impulses, or psychosurgery; or influencing its responses with lifestyle changes. By far the most widely used biomedical treatments today are the drug therapies. Primary care providers prescribe most drugs for anxiety and depression, followed by psychiatrists and, in some states, psychologists.