Biolgical explanations of depression
- Created by: Hannah Jeffery
- Created on: 24-04-15 11:26
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- Biological factors to Depression
- Genetic factors
- that depression is inherited though genetic make-up
- McGuffin et al
- 177 sets of twins
- concordance rate was 46%
- suggesting a substantial heritable component
- could be due to comorbidity
- twins had the same childhood
- higher than the general populations life time risk of developing depression
- Having a first degree relative with depression increases a persons chances of becoming depressed
- The Diathesis stress model
- depression is caused by a pre-disposition eg a genetic link or a neurotransmitter dysfunction
- we well as a stressor which triggers the depression
- Kendler et al
- Virginia twin study
- women who had a pre-disposition to depression ie that had an identical twin who already had depression
- more likely to devlop depression when faced with a negative life event than females with out the pre-dispostion
- gender biased
- reductionist
- more likely to devlop depression when faced with a negative life event than females with out the pre-dispostion
- women who had a pre-disposition to depression ie that had an identical twin who already had depression
- Virginia twin study
- depression is caused by a pre-disposition eg a genetic link or a neurotransmitter dysfunction
- Suicidal gene
- Royal Ottawa Hospital
- Mutation in the gene that is a serotonin receptor
- Suicidal tendencies were more common in people with the mutation on the gene
- high every day life application
- moral implications
- Hrdina
- long term study on 120 depressed Canadians
- gene doubled the risk of suicidal tendencies
- ignores social-psychological factors
- cannot establish cause and effect
- Biochemical factors
- comer suggests depression is due to low activity of certain monoamine neurotransmitters
- eg noradrenaline and serotonin
- serotonin can be influenced by the sun
- season affective disorder
- serotonin can be influenced by the sun
- neurotransmitters help to regulate the hypothalamus
- crucial for the nervous and endocrine system
- explains the disruption od sleep, appetite and physical movement
- crucial for the nervous and endocrine system
- supported by the effectiveness of anti-depressants
- Thase and Kuffer
- anti-depressants reduced the symptoms of depression more than a placebo
- Brunney at al
- low levels of noradrenaline in depressed individuals
- Delgado
- depressed patients were receiving antidepressants were given a diet that would decrease their serotonin levels
- while on the diet their depression symptoms returned and they went back to normal after going off the diet
- however people with no pre-disposition show little mood change
- rot et al suggest that a depressive episode alters the serotonin system and makes individuals more vulnerable
- depressed patients were receiving antidepressants were given a diet that would decrease their serotonin levels
- eg noradrenaline and serotonin
- Cortisol hypersecretion
- elevated levels of the stress hormone in depressed individuals
- levels disappear when depression disappears
- however Strickland found no evidence
- however they did find high levels in individuals who'd experienced stressful life events
- females areas twice as likely than men t develop depression
- eg prementral syndrome and post-natal depression
- Gotlib says that females who suffer postnatal depression have a pre-disposition
- still only 10-15% of population
- eg prementral syndrome and post-natal depression
- comer suggests depression is due to low activity of certain monoamine neurotransmitters
- Evolutionary response
- Adaptive
- individuals experience higher levels of psychological functioning after than before hand
- increases help and support
- strengthens the individual
- costly process
- Adaptive
- Genetic factors
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