The effects of major depressive disorder can descend upon a person even when it would appear that everything is going well in his or her life.

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Sadness is an emotion that everyone has felt at some point in their lives. It's a natural response to events that can range from teenage heartbreak to the death of a loved one or the loss of a pet. A child may feel it if his balloon pops or her ice cream cone slips out of her hand and plops on the sidewalk. An entire community may feel it after a natural disaster. Sadness isn't pleasant, but it's directly attributable to a particular event; it can come in varying degrees, and it can actually serve a beneficial purpose not unlike cleansing a physical wound helps lead to healing.

Major depressive disorder (MDD) shares some traits with sadness but also has some distinct differences. Failing to recognize those differences can lead to false self-diagnosis. It can also result in the stigmatization of a person by society. It's all too easy to say, "I've been sad before, but I got over it and got on with my life ... that's what Jane should do, too, but she likes to wallow in it." In many cases, the stigma is that a person dealing with depression is weak or lacks strong character [source: Payne]. Neither assumption is correct.

The causes of, and treatment options for, MDD tend to vary. Much research has been done in the field of depression and enormous progress has been made. But while an ear, nose and throat doctor can run a test to determine if you have strep throat or an orthopedist can diagnose a broken leg, your doctor can't test your blood for major depressive disorder. The diagnosis, causes and treatments for major depressive disorder are often more nebulous and difficult to understand.

It's valuable, however, to learn as much about depression as possible. Without a proper understanding of the condition, stigmas persist and opportunities to improve qualities of life are squandered. One of the myths associated with MDD is that people who have it won't ever be able to get rid of it [source: Payne]. It's true that there isn't a one-size-fits-all approach to treatment, but that doesn't mean it can't be treated.

There are definable criteria for major depressive order, as well as researched and substantiated causes of the condition. In addition, effective, tested solutions are available in a variety of forms. In short, if you or someone you know is battling something more severe than what seems to be typical sadness, there are ways to recognize it, figure out where it came from and find hope for an improved quality of life.