Depression is a medical condition that affects a per-son’s thoughts and feelings as well as the body. It can be associated with various physical problems in areas such as sleep, appetite, energy, libido, and thinking. Research increasingly demonstrates that depression is not a condition resulting from personal or moral weakness but is a treatable illness. Although it is often associated with feelings of sadness or the “blues,” it is not the same thing.
The best way to characterize clinical depression from normal sadness is to think of the term depression in a global, bodily sense, where there is a reduction in physiologic activity across a variety of physical systems, including emotion and cognition. Although stressors can trigger an episode of depression, the stressful life event alone does not cause the condition. Anyone is susceptible to depression, although certain populations are at a higher risk. Untreated, depression can last for weeks, months, or years. Many people have recurrent episodes. As with any illness, both morbidity and mortality are associated with depression.
Morbidity is a result of the functional impairment that a person experiences in areas of work, school, and relationships. Mortality is due to death by suicide or accidental death because of the functional impairments (e.g., car accident, illicit drug use, poor nutrition, and neglect of health). Most people who are depressed respond to treatment, and thus it is unwarranted for anyone to suffer through an episode. The affected person may believe that no one else suffers in the same way and that he or she is alone in having depression.
However, depression is a common illness around the world. The lifetime prevalence for depression is approximately 15%, and in any given 1-year period 18.8 million adults in the United States suffer from depression. Close to 25% of persons seeking medical treatment in their primary care doc-tor’s office suffer from depression. Not only does depression have a personal cost on individuals and their families, it has a significant cost on society.
Because many people who are depressed do not seek treatment, the cost of untreated depression to society runs into tens of billions of dollars, in part because of decreased productivity at work and overuse of primary healthcare services. Only approximately half of people with major depression ever receive specific treatment, because symptoms of depression may be inappropriately dis-missed as understandable reactions to stress, evidence of personal weakness, or an attempt to receive secondary gain (such as attention from others or disability payments).