Outline and Evaluate the Biological Explanation for Depression

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Biological explanations of depression – (Biochemical) The biochemical explanation claims that depression is the cognitive state resulting from imbalances in brain chemistry that can be controlled in many cases by antidepressant drugs known as tricyclic drugs. However, it does not claim these imbalances are genetic in origin – and, indeed, they may be the consequence rather than the cause of some aspects of depression. There are three brain chemicals principally involved. These are noradrenalin, serotonin and dopamine. Post-mortems of depressed people do not show abnormally low levels of noradrenalin. Serotonin levels are also associated with depressive symptoms, but we do not know whether a low serotonin level is the cause or consequence of depression. According to Iverson, low dopamine levels are associated with unipolar depression. Cases of depression in old age were thought to be associated with the fact that dopamine production naturally diminishes after the age of 45. However, giving elderly people a replacement for dopamine doesn’t seem to help. Although these three neurotransmitters may be involved in depression we do not know how. Researchers investigating the endocrine (hormonal) system have found that the adrenal cortex produces cortisol and cortisone – two hormones involved in metabolism of fats, carbohydrates and proteins. Cortisol production is increased as the individual experiences stress, and this may trigger other psychological responses leading to the experience of depression. Hormonal (oestrogen and progesterone) imbalances are known to be involved in some menstruation-related depression, although the precise involvement is not known. Some people appear to become more depressed and lethargic and have trouble sleeping during winter months. This pattern can indicate a mood disorder called seasonal affective disorder (SAD). One suggestion is
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