What is Major Depression?
Major depression is a serious medical illness affecting 9.9 million American adults, or approximately five percent of the adult population in a given year. Unlike normal emotional experiences of sadness, loss, or passing mood states, major depression is persistent and can significantly interfere with an individual's thoughts, behavior, mood, activity, and physical health. Among all medical illnesses, major depression is the leading cause of disability in the U.S. and many other developed countries.
More than twice as many women (6.7 million) as men (3.2 million) suffer from major depressive disorder each year. Major depression can occur at any age including childhood, the teenage years and adulthood. All ethnic, racial and socioeconomic groups suffer from depression. About three-fourths of those who experience a first episode of depression will have at least one other episode in their lives. Some individuals may have several episodes in the course of a year. Left untreated, depression can lead to suicide.
Major depression, also known as clinical depression or unipolar depression, is only one type of depressive disorder. Other depressive disorders include dysthymia (chronic, less severe depression) and bipolar depression (the depressed phase of bipolar disorder or manic depression). People who have bipolar disorder experience both depression and mania. Mania involves abnormally and presistently elevated mood or irriability, elevated self-esteem, and excessive energy, thoughts, and talking.
What are the symptoms of major depression?
The onset of the first episode of major depression may not be obvious if it is gradual or mild. The symptoms of major depression characteristically represent a significant change from how a person functioned before the illness. The symptoms of depression include:
- Persistently sad or irritable mood.
- Pronounced changes in sleep, appetite, and energy.
- Difficulty thinking, concentrating, and remembering.
- Physical slowing or agitation.
- Lack of interest in or pleasure from activities that were once enjoyed.
- Feelings of guilt, worthlessness, hopelessness, and emptiness.
- Recurrent thoughts of death or suicide.
- Persistent physical symptoms that do not respond to treatment, such as headaches, digestive disorders, and chronic pain.
When several of these symptoms of depressive disorder occur at the same time, last longer than two weeks, and interfere with ordinary functioning, professional treatment is needed.
What are the causes of major depression?
There is no single cause of major depression. Psychological, biological, and environmental factors may all contribute to its development. Whatever the specific causes of depression, scientific research has firmly established that major depression is a biological brain disorder.
Norepinephrine, serotonin, and dopamine are three neurotransmitters (chemical messengers that transmit electrical signals between brain cells) thought to be involved with major depression. Scientists believe that if there is a chemical imbalance in these neurotransmitters, then clinical states of depression result. Antidepressant medications work by increasing the availability of neurotransmitters or by changing the sensitivity of the receptors for these chemical messengers.
Scientists have also found evidence of a genetic predisposition to major depression. l There is an increased risk for developing depression when there is a family history of the illness. Not everyone with a genetic predisposition develops depression, but some people probably have a biological make-up that leaves them particulary vulnerable to developing depression. Life events, such as the death of a loved one, a major loss or change, chronic stress, and alcohol and drug abuse, may trigger episodes of depression. Some illnesses such as heart disease and cancer and some medications may also trigger depressive episodes. It is also important to note that many depressive episodes occure spontaneously and are not triggered by a life crisis.
