If you're taking an antidepressant, cut back or eliminate alcohol. Alcohol is a depressant and can worsen feelings of sadness.

Serious depression is more than feeling sad the way we all do sometimes. Depression can descend without apparent cause, and blot out happiness and purpose for months at a time. In bad cases, it interferes with memory, concentration, and motivation, and keeps you from working, playing, or participating in life.

This kind of depression, once considered the result of a mental weakness or character flaw, is now understood to be a biological illness—and unfortunately a very common one. One in six Americans suffers major depression at some time in life. And in any given year about 18 million people, or 6 percent of us, have an episode that warrants treatment. For some, depression is a chronic illness that recurs over years. If untreated or poorly treated, depression can be deadly, too. People with recurrent bouts are prone to earlier death from heart and other ailments, not to mention the increased risk of suicide.

The most common treatments are psychotherapy, counseling, and antidepressant drugs. Studies show the medications work best when paired with at least several months of therapy, and experts recommend this approach. But most people prefer to start with a medicine alone, and many doctors are willing to go along. As a result, antidepressants have become one of the most widely prescribed types of drugs in the country. Their use has more than tripled in the last two decades.