Final answer:
After three weekly sessions of ECT for 2 to 4 weeks, over 80 percent of individuals with severe depression show significant improvement. ECT alters brain chemistry, which can rapidly alleviate depressive symptoms.
Step-by-step explanation:
After three sessions of Electroconvulsive Therapy (ECT) each week for 2 to 4 weeks, 80 percent or more people suffering from severe depression improve markedly. ECT is a form of medical treatment for major depressive disorder which involves electrical stimulation of the brain while the patient is under anesthesia. Although its exact mechanisms are not fully understood, ECT is believed to work by altering brain chemistry, which can quickly reverse symptoms of severe depression. Treatments for depression vary and can also include psychotherapy, deep-brain stimulation, and prescription medications like monoamine oxidase inhibitors and selective serotonin reuptake inhibitors.