Antidepressants are prescribed, and often combined with therapy , to manage depression, which is a common condition that impacts millions of people every year, according to the American Addiction Centers. The World Health Organization notes that antidepressants are one means of treating depression , among many other options, such as structured therapy and behavioral actions and changes. Harvard Health says that antidepressants work by regulating mood by targeting specific messaging systems in your brain. They are among the most prescribed medicines in America, but ultimately treatment for depression varies in effectiveness depending on the individual. “We can't predict exactly how someone will respond to treatment because we're all biologically different," Dr. Michael Craig Miller, assistant professor of psychiatry at Harvard Medical School, told Harvard Health. "Medicine is only one tool . Psychotherapy can help you examine the patterns in life that may be making you feel down. And don't forget about the benefits of exercise, a balanced diet, and engaging in meaningful activities. They fight depression."