When medication fails to ease the symptoms of clinical depression, there are other options to try. Brain stimulation techniques such as electroconvulsive therapy (ECT), for example, can be used to treat major depression that hasn't responded to standard treatments.

The least invasive of these techniques is called transcranial magnetic stimulation (TMS), in which a magnetic field is created by a device held above the head, causing a weak electrical signal to be applied to the prefrontal cortex, the region of the brain that is connected to mood.

Vagus nerve stimulation (VNS) is another treatment for depression that uses a surgically implanted pacemaker-like device that electrically stimulates a nerve that runs up the neck into the brain. The nerve is called the vagus nerve. With ECT, an electric current is briefly applied through the scalp to the brain, inducing a seizure.

In addition, alternative therapies such as yoga and hypnosis sometimes work for mild depression.