Depression is a mental health disorder defined as prolonged periods of intense sadness. The overwhelming feeling of sadness or hopelessness in depression is out of proportion to the event that causes it, with feelings lasting beyond an appropriate amount of time. Reactive depression is a milder form of depression in response to a specific major life stress or loss, and typically resolves. Major depression, on the other hand, is a serious and disabling illness.
Depression is classified as a mood disorder. It is the second most common mood disorder after anxiety disorders. About 10% of the U.S. population experience depression severe enough to require medical attention. Depression is most common among people in their 20s, 30s, or 40s but can begin at any age and is often seen in the elderly. Careful research studies have shown that depression is more common among women than among men.
In patients with major depression, the episodes of depression tend to come and go throughout the person's lifetime; symptoms typically last 6 months if untreated. However, sometimes depression can last 2 years or more. Most cases of reactive depression resolve with time and resolution of the inciting event or situation.
A number of factors may lead to depression, including family history (heredity), side effects of certain drugs, changes in hormone levels, and emotionally distressing events, such as a loss of a loved one, job, or other major career change. In patients with major depression, there may be no specific event leading to a depressive episode.
There are several types of depression, including transient (reactive) depression, postpartum depression, dysthymia, seasonal affective disorder, and major depression. Major depression accompanied by delusions or hallucinations is called psychotic depression.
Symptoms of depression include sleep disturbances, change in appetite (both increase and decrease), fatigue, feelings of worthlessness, difficulty concentrating, irritability, loss of interest in activities or hobbies, and feelings of hopelessness. Depression may prevent a person from feeling emotion in a normal way. Because people with depression often have feelings of worthlessness and low self-esteem, they may also have thoughts about death and suicide. Hence, depression, especially major depression, can increase a person's risk for suicide. A suicide threat from a person who is depressed should never be ignored.
