Depression: Nature or Nurture?
The true cause of depression continues to evade modern medical science. While there are many known risk factors for depression, such as stress, genetics, environment, hormone fluctuations and chemical imbalances in the brain, everyone responds to these factors differently.
Is Depression Hereditary?
Depression and associated mood disorders do tend to run in families, which suggests that some depressive disorders are inherited. People are up to three times more likely to get depressed if
they have a first-degree relative (sibling, parent) who suffered from depression. Studies done on identical twins show a strong likelihood for one twin to suffer from depression if the other twin does. However, genetics can't explain every case of depression; a person with no family history of the condition can still suffer from it.
Chemical Imbalances and Neurological Conditions
Still other studies look inside the brain to find causes of depression. Brain scans reveal that the depressed individual's brain undergoes some startling changes. The areas that regulate behavior, appetite, cognitive function, and mood are all altered due to changes in brain chemistry. Depression alters neurotransmitter levels, and most antidepressant drugs work by regulating the levels of neurotransmitters (such as serotonin).
Hormone Fluctuations
There is also a theory that suggests depression can be caused by changes in hormone levels. For instance, postpartum depression can happen after a woman's hormone levels fall flat in the weeks after she gives birth. While some mothers suffer from full clinical depression, most just go through a short bout of the "baby blues". It remains to be discovered why some women are more vulnerable to postpartum depression than others are.
Environmental Causes
Of the four main causes of depression, environmental factors are the hardest to pinpoint. Stress, socioeconomic issues, the death of a friend or relative- all of these can send someone into a depressive episode. Depression is often an accompaniment to other illnesses, but not all people get depressed even if they are undergoing the same stresses.
It's looking more and more likely that there is no single cause for depression, and that depressive episodes are triggered by a complex blend of brain chemistry alterations, hormonal triggers, genetics and environment. Some believe that pinpointing a cause for depression is less vital than finding a cure, but understanding what may cause the condition allows medical professionals to formulate more effective treatment plans.