Depression, a state of feeling sad is a common mood swing and is virtually experienced by all of us at some point in our life. Depression can be present in a person in different forms regarding its severity and duration. A constant and prolonged form of feeling low and sad is taken as a serious behavioral problem and should be treated promptly.

Major depressive disorder is a medical condition characterized by a combination of abnormalities like persistent sadness, constant despair and loss of interest in routine activities, sleep disturbances, feelings of being useless and agitation.  It is also known as clinical depression or unipolar depression. The person affected by clinical depression finds it difficult to study, sleep, work, eat, enjoy with family and carry on the day-to-day activities.

Some patients experience only one episode of depressive disorders, while other may have recurrent attacks. Major depressive disorder is one of the main depressive disorders. Other depressive disorders include bipolar depressive disorder, dysthymic disorder and minor depressive disorder.


The exact figure of people that are affected by depressive disorders is not known. The date varies from country to country. However, it is an established fact that depression is a common problem affecting people all over the world.

According to national institute of mental health, about 6.7% adults in America have had such depressive problem. The national institute for clinical excellence reports that the combined prevalence of depression and anxiety is 98 per 1000 in the United Kingdom.

What causes the depressive disorder?

There is no single definitive cause for major depressive disorder; rather it is caused by a combination of different genetic and environmental disorders. Major depression affects women twice as compared to men for unknown reasons. The main cause is thought to be the imbalances in neurotransmitters such as norepinephrine, dopamine and serotonin. The strong family history of depression is also suggestive of genetic tendency to develop this depressive disorder. Some of the major causative agents may include:

  • Abnormal levels of neurotransmitters in brain
  • Biological difference in brain
  • Hormonal imbalance
  • Inheritance
  • Emotional trauma
  • Drug abuse