Depression is a mental illness thought to be caused by a combination of things, from psychological to biological factors as well as your genetics and your environment. It's considered a neuropsychiatric illness.
The treatment for neuropsychiatric illnesses such as depression varies from person to person, based on each individual's symptoms and the severity. Major depression can be -- and commonly is -- successfully managed with either psychotropic medications (such as antidepressants to help re-balance neurotransmitters in the brain) or psychotherapy (also called "talk therapy," including cognitive-behavioral therapy and interpersonal therapy), or a combination of both drug and talk therapies.
Catatonic depression often responds well to psychotropic drug therapies, including benzodiazepines, anticonvulsants and antiepileptics. When depression is complicated by symptoms of catatonia, mental health professionals have found that a once maligned therapy -- neurostimulation -- often has a high success rate for relieving symptoms. Electroconvulsive therapy (ECT), sometimes called shock therapy, is a form of neurostimulation therapy.
ECT has changed over the years, and despite its formerly bad reputation, it can be a successful treatment for people who need immediate treatment, people with severe depression or people who aren't improving with medication and psychotherapy alone (known as treatment-resistant depression).
ECT works by causing a seizure in the brain. During this treatment, patients are placed under general anesthesia and an electrical current is administered to the brain through electrode pads that are affixed to the head. This causes a seizure. While it is known that ECT affects many of the body's systems, including the central nervous system and neurotransmitter systems, the reason why ECT is successful in treating symptoms of catatonic depression still remains unclear. One theory is that the changes made by the the electrical current to the body's neurotransmitter systems helps to relieve symptoms. Think of it as if the electrical current rebooted those systems similar to the way you might think of a computer rebooting.
There is often no single treatment for major depression with catatonic features, though, and some patients may find the most benefit from multiple therapies at the same time.