Explain the biological basis of Depression.

To answer this question I would split the answer into two sections: genetic explanations and bio-chemical explanations for depression.- There is a genetic element to the development of depression which can be seen in the findings of family, twin, and adoption studies. This means that a certain gene or combination of genes an individual posesses increases their vulnerability to depression. - This claim should be supported by research evidence - for example Wender et al found that adopted individuals were 7 times more likely to experience depression if their biological parents were also depressed. McGuffin et al found in 177 participants with depression who had a same sex co-twin, the concordance rate for depression was 56% in monozygotic twins (those with exactly the same genes) and 20% for dizygotic twins (those who have the same amount of genetic variation as normal sibilings)- There is also a bio-chemical explanation for depression which focuses on the infleunce of neurotransmitters and hormones in the onset of depression. - The monoamines (a group of neurotransmitters, including serotonin, nor-adrenaline, and dopamine) are believed to be unbalanced in the lower brains of depressed individuals. Studies have linked depression to low levels of nor-adrenalin and serotonin. -Bunney et al found that there were lower levels of noradrenaline in the waste products associated with this neurotransmitter- Mcneal and Cimbolic found sufferers of depression showed lower levels of 5-HIAA (found when serotonin is broken down) in the cerebrospinal fluid compared to those who didnt suffer from depression.- Cortisol (a hormone released during the body's stress response) is associated with the onset of depression. Since depression frequently follows long term stress, it could be suggested that exposure to cortisol causes depression.- If this is a long answer question, more research findings should be used to make evaluative points, whether it supports or refutes the explanation for depression.