Psychology Aqa a A2 Biological Explanations for Depression Essay

1744 WordsMay 17, 20157 Pages
Genetic factors A01 – Family studies >having a 1st degree relative (parent or sibling) with depression appears to be a risk factor for depression >the studies select people who already have depression (probands), and then examine whether other family members have been, or might be, diagnosed with depression -if there is a genetic link for this disorder, the probands’ relatives should show higher rates of depression than the rest of the population Harrington et al (1993) >found that around 20% of proband’s close relatives have depression compared to 10% for the general population A01 – Twin studies >basis is that identical (monozygotic) twins are clones of each other and have all the same genes -fraternal (dizygotic) twins share just half of their genes -we assume that the environment shared by the twins is roughly the same for both types of twin McGuffin et al (1996) >studied 177 probands with depression with their same-sex co-twins >concordance rate was 46% for identical twins and 20% for fraternal twins >suggest that depression has a large heritable component A01 – Adoption studies Wender et al (1986) >studies the biological relatives of adopted individuals who had been hospitalised for severe depression >found a much higher rate of severe depression in the biological relatives of the depressed group than in the biological relatives of a non-depressed control group (nature may be a stronger component than nurture) Genetic factors A01 – Family studies >having a 1st degree relative (parent or sibling) with depression appears to be a risk factor for depression >the studies select people who already have depression (probands), and then examine whether other family members have been, or might be, diagnosed with depression -if there is a genetic link for this disorder, the probands’
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