Most likely, depression is affected by a combination of genetic, biological, environmental, and psychological factors.
Depressive sicknesses are disorders of the brain. Brain-imaging technologies, such as magnetic resonance imaging (MRI), have shown that the brains of people who have depression look different than those of people without depression. The parts of the brain involved in mood, thinking, sleep, appetite, and behavior appear different. But these images do not reveal why the depression has occurred. They cannot be used to diagnose depression.
Some types of depression tend to run in families. However, depression can occur in people without family histories of depression too. Scientists are studying certain genes that may make some people more inclined to depression. Some genetics research indicates that risk for depression results from the influence of several genes acting together with environmental or other factors. In addition, trauma, loss of a loved one, a complicated relationship, or any stressful situation may trigger a depressive episode. Other depressive episodes may occur with or without an obvious trigger.
Major Causes of Depression
Some of the major causes are listed below.
Life events – Research suggests that continuing difficulties which can include long-term unemployment, living in an abusive or complicated relationship, long-term isolation, prolonged exposure to stress at work, are more likely to cause depression. However, recent events (such as losing a job) or a combination of events can ‘trigger’ depression in people who are already at risk because of past bad experiences or personal factors.
Family history – Depression can run in families and some people will be at an increased genetic risk. However, this doesn’t mean that a person will automatically experience depression if a parent or close relative has had the illness. Life circumstances and other personal factors are still likely to have an important influence.
Personality – Some people may be more at risk of depression because of their personality, particularly if they have a tendency to worry a lot, have low self-esteem, are perfectionists, are sensitive to personal criticism, or are self-critical and negative.
Serious medical illness – Having a medical illness can trigger depression in two ways. Serious illnesses can bring about depression directly, or can contribute to depression through associated stress and worry, especially if it involves long-term management of the illness and/or chronic pain.
Drug and alcohol use – Drug and alcohol use can both lead to and result from depression. Many people with depression also have drug and alcohol problems.
Changes in the brain – Although there has been a lot of research in this complex area, there is still much that we do not know. Depression is not simply the result of a ‘chemical imbalance’, for example because you have too much or not enough of a particular brain chemical. There are in fact many and multiple causes of major depression. Factors such as genetic liability, severe life stressors, and substances a person may take (some medications, drugs and alcohol) and medical conditions can lead to broken down mood regulation in the brain.
Effective treatments can stimulate new growth of nerve cells in circuits that regulate mood, which is thought to play a critical part in recovery from the most severe episodes of depression.
Everyone is different and it’s often a combination of factors that can contribute to a person developing depression. It’s important to note that you can’t always identify the cause of depression or change difficult circumstances. The most important thing is to recognize the signs and symptoms and seek help.