Read Our Privacy Policy. Back to Depression. Depression major depressive disorder is a common and serious medical illness that negatively affects how you feel, the way you think and how you act. Fortunately, it is also treatable. It can lead to a variety of emotional and physical problems and can decrease your ability to function at work and at home.

Symptoms of depression often overlap with those of ADHD, making an accurate diagnosis challenging. Roughly one quarter of all adults with ADHD also experience symptoms of depression , which include feelings of sadness that last most of the day, stretch into weeks, and interfere with daily life. Depression, which typically begins to manifest around age 18, causes the sufferer and his or her loved ones significant pain. It is a serious illness that requires swift diagnosis and treatment; depression is a leading cause of suicide among adults.

As you get older, you may go through a lot of changes—death of loved ones, retirement, stressful life events, or medical problems. But after adjusting, many older adults feel well again. Depression is different.