UNDERSTANDING DEPRESSION
The Causes of Depression
Neurotransmiters
Brain Monoamine is found to have a direct role in depression.
Heniger et al (1996)
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Aim: To test effect of monoamine depletion and the effects of monoamine on depression
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Procedure : Reduced monamine level to see the effect of them on those currently suffering from depression, recovered from depression and those without depression
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Result: Relapse to serotonin depletion or catecholamine depletion is specific to the antidepressant
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Healthy people were not affected
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Recovered patient were more subjected to relapsed
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depressed patients did not get worst
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if patient had taken medication with serotonin inhibitor then they are more susceptible to relapses
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Implication: Monoamine does have an effect on depression, but not the only reason
Genetics
Genettic causes of depression is investigated using twin studies
Sullivan
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Aim: A meta-analysis of twin studies to investigate genetic cuases
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Results:
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MZ twins were more likely to develope major depression than DZ twins
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Genetic influence in developing major depression was between 37%
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Environment also has an effect
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Implication: Depressionvie familial disorder with genetic components and to some extent environemntal component
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Aim: Investigate the effectiness of SSRI in depression
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Procedure: A metaanalysis on studies that tested the effect of anti depressants
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Result: 57% of the studies failed to show a statistical difference between the anti depressants and a neutral placebo
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Serotonin may not be a strong cause of depression
Kirsch et al ( 2002)
MZ: Monozygotic twins share 100% of genetic material
DZ:Dizygotic twins share 50% of genetic material