biological

• the biological explanation says that behaviours have a physical cause. the genetic explanation focuses on the idea that vulnerability to depression is inherited. twin and adoption studies are used to research this. gene mapping has also been used to identify which gene might be responsible
• Wender


  adopted children who develop depression were more likely to have a depressive biological parent

  despite being raised in a seperate environment

  biological factors are more important than cognitive ones
• McGuffin et al

  46 % concordance for MZ twins compared to 20 % in DZ for depression. however, it might be the case tht cognitive issues come from biological faults
• Plomin


  used gene mapping techniques on 3154 pairs of 12 year old twins

  genetics accounted for around 66 % of the heritability of cognitive abilities. the similarity of symptoms was the same regardless of age, gender and cultural groups. as well as the similarity in physical symptoms, suggesting genetic influence. howeever, if it was purely genetic, concordance would be 100 %
• evidence suggests a strong link between low levels of seretonin and depression. low seretonin levels are likely to have a genetic basis. depression is regularly treated by using antidepressants and the effectiveness of these is strong evidence for the neural explanation
• evaluate the neural explanation:

  + scientific evidence to support it

  - reductionist and deterministic

  - ignores social and environmental factors causing depression

  - implies depression is an illness which comes with a stigma attached