There has been a great deal of research into the causes of depression but there is still no precise known cause for depressive disorders. There may be no single cause that can be easily cured with depression so researchers are working to find out what possibilities exist to improve treatment and look for a cure to depression.
Since depression is no longer thought to be caused by troubling thoughts or emotions, medical and mental health professionals are looking into the factors that contribute to the risk of developing depressive illnesses. The majority of findings suggest that there are three main factors at work: biology, genetics and environment. These factors may cause depression individually or as a combination of the group.
Biology
Changes that take place in the brain can cause depressive episodes. An imbalance in hormones or chemicals can cause the brain to react improperly or disconnect behavioral mechanisms which can be causes of depression. Research shows that imbalances related to neurotransmitters (which allow brain cells to communicate) known as serotonin and norepinephrine.
A deficiency in serotonin can cause sleep problems and the side effects from lack of sleep, irritability and anxiety, and a deficiency in norepinephrine can result in fatigue and depressed mood. These are all common symptoms of depression. Cortisol (the hormone related to stress response) reacts differently in people who are depressed than those who are not.
The hormone levels peak earlier and do not markedly decrease as the day wears on, leaving the person with higher responses to fear, anger and stressors. Whether the changes cause depression, or are caused by the depression, remains to be seen.
Genetics
If one or both of your parents has a history of depressive or other mental disorders in their family (or has a disorder themselves) you have an increased chance of developing these disorders. Researchers are searching the human genome for markers related to depressive disorder risk. Since there is a hereditary link that increases the chance of being diagnosed with depression, there should be some evidence of this on the most basic level of human cellular development.
Environmental
Having had a stressful encounter or event in your life can cause a depressive episode. Things like deprivation of parental affection, death, loss, beak ups, job stress and abuse can cause depression. Physical illness, loss of limb or even medication can be a cause of depression. A combination of these events, genetics and biological factors can trigger depressive episodes.
Differences
One thing noted in research on the causes of depression is that there are physical differences in the brains of people who suffer from depression that are not found in the brains of people who do not. One example is the hippocampus, the part of the brain responsible for memory storage.
The hippocampus is smaller in individuals who have depression. This may be caused by the excess of cortisol found in the brain; cortisol is believed to have a negative effect on the hippocampus. This is important because a hippocampus has fewer serotonin receptors which results in a decrease of serotonin in the brain, resulting in the detrimental side effects of depression.
Other Causes of Depression
Biology, genetics and environment are the three main causes of depression, but other things can trigger a depressive episode.
They include:
Stress/Trauma – relationship, work related and financial problems are known stressors that can trigger depression. Negative changes like loss of a relationship through separation, divorce or death can cause depression as can positive changes like graduation, marriage and getting a new job.
Personality – if you have a pessimistic personality, low self esteem and a generally low outlook on life you are at higher risk for developing depression; in particular chronic depression
Physical – having a serious disease (like cancer, HIV or heart disease) can trigger depression due to weakness and loss of ability in the body. These diseases can weaken your immune system and make it harder to deal with the trials of the disease and have medications that contribute causes of depression. |
