Depression is most often treated with psychotherapy (talk-therapy) and antidepressant medications administered together. Although antidepressants can be effective for many patients, they do not work for everybody. Additionally, since antidepressants are typically taken by mouth, they circulate in the bloodstream throughout the body, often resulting in unwanted side effects. More than 4 million patients do not receive adequate benefit from antidepressant medications and/or cannot tolerate the side effects caused by them. For these patients, alternative treatments are available which usually involve the use of a medical device. These treatments include: transcranial magnetic stimulation (TMS), electroconvulsive therapy (ECT) and vagus nerve stimulation (VNS).