Biological explanations of depression
- Created by: 08rmorris
- Created on: 05-04-15 14:15
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- Biological explanations of depression
- Genetic factors
- Being biologically relate to someone who has depression seems to increase a person's chase of developing it
- Evidence for
- McGuffin et al (1996) found that if one MZ twin has MDD, then in 46% of cases the other twin would be diagnosed as well
- For DZ twins the concordance rate is about 26%
- Wender et al (1986) studied biological parents of adopted children who had MDD
- the biological parents were 8X more likely to have depression than the children's adopted parents
- McGuffin et al (1996) found that if one MZ twin has MDD, then in 46% of cases the other twin would be diagnosed as well
- Evidence against
- The concordance rates found in family and twin studies aren't 100%, so genetics cant be the whole story. Environmental factors play a role
- Genetic factors only seem to explain endogenous depression (caused by internal factors) - psychological factors seem to have more influence in development of reactive depression
- Biochemical factors
- Low levels of serotonin have been linked to depression
- Kety (1975) developed the permissive amine theory, which states that serotonin controls the levels of the NT noradrenaline
- A low level of serotonin cause the levels of noradrenaline to fluctuate
- Low levels of noradrenaline then cause depression
- high levels of noradrenaline cause mania
- A low level of serotonin cause the levels of noradrenaline to fluctuate
- Kety (1975) developed the permissive amine theory, which states that serotonin controls the levels of the NT noradrenaline
- Evidence for
- Anti-depressant drugs work by increasing the availability of seotonin at the synapses by preventing its reuptake or breakdown
- This suggests that it's the low levels of serotonin that lead to depressive disorders
- Post-mortems carried out on people who committed suicide have shown abnormally low levels of serotonin
- Suggesting that this may have caused their depression
- Anti-depressant drugs work by increasing the availability of seotonin at the synapses by preventing its reuptake or breakdown
- Evidence against
- Just because anti-depressants relive the symptoms does not mean they treat the cause
- Low levels of serotonin could be a result of depression not the cause
- Psychological research has found alternative explanations for the cause of depression
- Low levels of serotonin have been linked to depression
- Genetic factors
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