Major depression is unlike the normal feelings of sadness, loss, or passing mood states that most people have. The condition is more persistent and because of that persistence, it could significantly interfere with your thoughts, behavior, mood, activity, and even physical health. According to the World Health Organization (WHO), major depression is set to become the second leading cause of disability in the world, after heart illness.

When suffering from clinical depression, people have different ways of confronting it. Some acknowledge it, face it just like any problem, and seek help. Some ignore it as if it doesn't exist. And others simply accept that it's there but they don't do anything about it. In fact, they don't even ask for help. Those who ignore and don't do anything run the risk of developing the serious complications of depression. Like any medical disorder, untreated clinical depression has its hazards.

Chronic Depression

According to the landmark "Global Burden of Disease" study, mental disorders are the second leading source of disease burden in established market economies and major depression alone ranked as the leading causes of disability. Major depression takes an enormous toll on functional status, productivity, and quality of life, and is associated with elevated risk of heart disease and suicide.

Symptoms

The onset of major depression may be gradual so the symptoms are not immediately obvious. However, some of the signs to look out for to determine whether you are suffering from major depression or not include the following:

• Persistently sad mood, or high irritability

• Marked changes in normal habits, including sleep and appetite

• Pronounced changes in energy; often low energy almost daily

• Feelings of being "slowed down" or agitation

• Loss of interest in previously pleasurable activities

• Persistent feelings of guilt, worthlessness, hopelessness, and emptiness

Causes

The causes of major depression are varied and the events that led to the development of the condition are sometimes too numerous to pinpoint a single one as the definitive cause. There are usually many factors involved – physical, biological, and even environmental factors all play a role.

According to scientific research, however, major depression is primarily a brain disorder. The problem could be traced back to three chemicals or neurotransmitters, which serve as messengers that transmit electric signals between brain cells. These are nor epinephrine, serotonin, and dopamine.

A person suffering from major depression often exhibits a chemical imbalance between these three neurotransmitters, thus producing a clinical state where depression occurs. It is not enough however to treat major depression through psychotherapeutic drugs alone.