Depression is a disorder that is evidenced by excessive sadness, loss of interest in enjoyable things, and low motivation.
It is normal to experience feelings of sadness and despair in response to adverse life events. Such events could include loss, major life changes, stress, or disappointment. In most cases, the sad feelings resolve as you come to terms with the changes in your life. In situations such as bereavement, these feelings may persist for months and return at significant times, such as birthdays and anniversaries related to the lost loved one. Provided you have times when you can enjoy things, however, this sadness is not a sign of depression.
Depression is common. One in three people will experience a major depressive episode at some stage in their lives. While most cases of depression are mild, about one person in ten will have a moderate or severe episode.
No one knows exactly what causes depression. It is clear that genetic factors are important in many cases of depression. Depression seems to run in families (as do other mood disorders), and about 30% of the predisposition for depression is due to genetic influences.
Stressful life events play a part in the onset or relapse of depression. Ongoing conflicts with others can take their toll on our well-being, as can other social and environmental stressors such as financial difficulties, retirement, unemployment, childbirth, loneliness, or loss of someone or something important. In vulnerable people, these unpleasant life events may be enough to cause or worsen a depressive illness.
A person’s personality characteristics are an important factor. When people are depressed, they usually have a very negative view of themselves and the world. They do not appreciate good things, and bad things seem overwhelming. Some people have a tendency to view things this way even when they are not depressed. In other words, they may have a depressive personality style.
Another possible cause of depression that should not be overlooked is physical illness or medications. Glandular fever, influenza, hepatitis, thyroid hormones, anaemia, diabetes, birth control pills, alcohol and other substances of abuse, or other medications such as those for heart or blood pressure conditions, may all cause symptoms of depression.