The causes of depression can be broadly segregated as biological, hereditary or environmental. In some people it might occur because one particular cause while in others due many causes, or for no particular cause at all. Depression is basically the result of changes in the brain connected to disproportion of neurotransmitters, which are responsible for carrying signal in the brain and nerves.

The major factors are:

Hereditary factors: Research gives concrete evidence that depression can be a part of the family traditions that you inherit. It's yet to be identified specifically which genes are involved in depression and the exact way in which depression is passed on in the family. However, it doesn't imply that you are bound to get it, if your family members suffered, nor does it mean that you can't, if you have no family history of this disorder.

Drugs and alcohol: Substance abuse is one of the most glaring causes of depression. Around 30% people, who are addicts, are likely to suffer from major clinical depression. Though is was always ascertained that people contract this ailment and then resort to alcohol and drug abuse, in most cases its vice-versa

Certain medications: Some types of medicines can cause depression or make it worse. Blood pressure drugs, sleeping pills, antibiotic medicines and some contraceptive pills can cause this disorder.

Personal situation: Certain situations in life like the loss of a loved one, a pink-slip, divorce, retirement etc can lead to mood swings and gradually depression. Astonishingly, certain happy situations like wedding, child-birth etc can also trigger it off.

Medical condition: Depression is perhaps the most obvious reaction to diseases, especially to the more sinister ones like cancer, Tuberculosis and diabetes. However is should not be considered as the standard or natural reaction and family members should be extra watchful in these situations.

Personality: certain individuals have character traits which trigger off depression. They might be prone to too much worry, pessimism, low self esteem and feelings of guilt and worthlessness. When people opt for an alienated lifestyle because of their hypersensitivity or perceived exclusion from the society, the chances of depression increase.

Learn more about causes of depression.