Monoamine Theory

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In the case study, the patient is diagnosed with depression when he goes to his GP nine months after his daughter’s death. Depression is a mood disorder, and according to the DSM-IV (1), a ‘major depressive episode’ is when an individual experiences at least two weeks of a depressed mood or anhedonia, with children and teenagers possibly experiencing irritability as opposed to sadness. In addition, at least four more symptoms must be present almost all day, every day, for a minimum of 2 weeks. Furthermore, the symptom(s) must be new or much worse than they had been before the depressive episode. The patient in the case study presents with insomnia, weight loss, feelings of guilt, exhaustion, frequently being tearful, and no longer enjoying…show more content…
Rang et al (2) state that the main biochemical theory is the monoamine theory with a functional deficit of the monoamine neurotransmitters noradrenaline, serotonin and dopamine causing depression. This theory came about from the observation that drugs which affected the monoamines in the brain led to either the onset or alleviation of symptoms of depression. There are, however, some problems with this theory. One such problem is that although antidepressants alter the levels of the neurotransmitters immediately, clinical effects take weeks to appear. Also, antidepressants do not work for everyone. Had depression been directly caused by neurotransmitter levels, there would be a higher success rate. Another issue is that not all patients have low levels, some patients actually have high levels of the neurotransmitters, norepinephrine in particular. (3) There may also be neuroendocrine mechanisms involved, with half of depressed patients usually having high levels of cortisol, and the concentration not falling as it should when dexamethasone, a synthetic steroid, is given. Cortisol levels usually decrease once the depressive episode has passed. In some depressed patients, the circadian rhythm of cortisol release is out of sync. Levels should be low at night but they may be constant or high. However, this is not limited to depression and other plasma hormones are also affected. (2,

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