Depression is an extremely complex disease. There is no single cause for depression. There are many different factors that can trigger depression.
Depression runs in family. If you have a family history of depression, you are more likely to get depression yourself. But not everyone who has the genetic makeup for depression gets depressed, it depends. Many people with no family history of depression can become depressed. So genes are not the single cause of depression.
Those who suffer a serious illness and experience a stressful life event tend to feel depressed. Difficult life events, such as parents divorce, separate, and death can lead to depression. Some people may become depressed for events like moving or changing schools.
Not getting along well with the friends, colleagues and partners may cause depression. If a person's relationship with their partner breaks down, they are likely to feel low, to stop seeing friends and family, and to start drinking more, all of which can make them feel even worse, and trigger depression. Personality traits such as introversion, low self-esteem, pessimism, and dependence contribute to depression. Those who have low self-esteem and a negative outlook are at higher risk of becoming depressed. People who feel that they have no control over negative events are very likely to become depressed. For some teens, a negative, stressful, or unhappy family atmosphere can affect their self-esteem and lead to depression.
Loneliness and isolation can trigger depression. Depression rates are higher among people who live alone and have a limited social network. But even people surrounded by family and friends are at risk for depression if those relationships are un-supportive.
Depression may be caused by serious medical conditions. Medical conditions can bring the physical weakness and stress, which are likely to lead to depression. Moreover, depression can make medical conditions worse, since it weakens the immune system and can make pain harder to bear.
Whatever its cause, depression is not just a state of mind. It is related to physical changes in the brain, and connected to an imbalance of a type of chemical that carries signals in your brain and nerves. To keep fit, you should avoid depression as possible as you can.