Depression is a mental illness in which a person experiences deep, unshakable sadness and diminished interest in nearly all activities. Depression usually begins during a person's 20's or 30's. The illness may come on slowly, then deepen gradually over months or years. On the other hand, it may erupt suddenly in a few weeks or days. There are 3 types of depression; major depression, Bipolar depression, and seasonal affective disorder. Many of them come from anxiety or a situation which caused the person to become extremely depressed. Seasonal affective disorder is felt only during autumn and winter, when there are few hours of daylight. Many things can cause depression. Sometimes it is caused from a high amount of stress and conflicts in a person's life. Some depressions seem to come suddenly, even when things are going well. Most psychologists believe depression results from an interaction between stressful life events and a person's biological and psychological vulnerabilities. Genes may also influence depression by causing abnormal activity in the brain. Neurotransmitters in the brain play an important role in regulating moods and emotions. Neurotransmitters involved in depression include norepinephrine, dopamine, and serotonin. It is suggested that depression results from lower than normal levels of these neurotransmitters in the brain. An imbalance of hormones may also play a role in depression. The only risk factor for depression is that if a person feels that they are hopeless, worthless, and are full of despair, the may think of or commit suicide. .
This issue usually takes place in a person's conscience and it is an emotional issue that the person deals with. This disorder often affects them socially and physically. Depression usually alters a person's appetite, sometimes increasing it, but usually reducing it.