Outline and evaluate one or more biological explanations for depression. In your evaluation you should refer to research evidence.

(8 marks + 16 marks)

The biological explanations for depression centre on the mood disorder being biologically caused. Genetic factors suggest that you are born with a biological weakness which makes you unable to resist stressors, which consequently leads to depression. This is known as the diathesis stress model. The main piece of research that supports this comes from the Maudsley Hospital twin register, where concordance rates of 46% were found in MZ twins and 20% in DZ twins. This suggest that depression must be passed on through genes if there is a high concordance rate between twins which share the same genetic makeup both having depression.

However, biological factors such as the amine hypothesis states that if amines such as serotonin and noradrenalin become unbalanced, they can lead to depression. PET scans support this idea as they show that low levels of serotonin are present in people that are depressed. Other supporting evidence is that drugs such as MAOI’s, which work by increasing the available amount of noradrenalin in the brain, were found to be effective in alleviating the symptoms of depression. A problem with this is that it doesn’t state whether it is cause or effect.

Significant support for the biological explanation ...

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Significant support for the biological explanation of depression comes from neuroendocrine factors. Cortisol levels are higher in depressed people. A stress reaction leads to the production of Cortisol, a key hormone in arousal. In normal people a mechanism prevents excessive or prolonged arousal in response to a stressor. In depressed people those levels are high and then go down after a depressive episode. When noradrenalin levels are low, the Cortisol levels can’t be regulated which suggests that it is linked to depression. A problem with this explanation is that it doesn’t state whether it is cause or effect.

There is significant evidence to suggest that the role of hormones, (primarily female hormones) play a role in the contraction and development of depression. The occurrence of depressive symptoms in some women in the premenstrual phase after giving birth, have led to speculation that ovarian hormones might play a role in depression. Only about 10-15% of women meet the criteria for MDD after child birth, so this is clearly not an inevitable reaction to hormonal fluctuations. It has been found that women who experience postpartum depression are usually also experiencing psychological difficulties and have had previous episodes of depression (Gotlib).

The final piece of evidence which supports the biological explanation for depression is that your mood is in the frontal lobe of the brain. People that suffered head injuries or strokes in the frontal parts of the brain have a strong likelihood of developing depression. Therefore brain damage to the front of the brain can cause depression (Starkstein and Robinson 1991). Powell and Miklowitz carried out a meta-analysis found a link between frontal lobe damage and depression.

There are numerous studies that support the suggestion that depression is biologically caused, but none of these studies have indicated why depression appears twice as common in women as in men.

Although there is a substantial amount of evidence to support the biological causes if depression, there are competing views about depression with a central viewpoint that it is unconscious forces and experiences during early childhood which contribute to the development of depression in adult life. This theory is heavily supported by the work of Freud.

Peer Reviews

Here's what a star student thought of this essay

sydneyhopcroft

25th of Jun 2012

Quality of writing

The Quality of Written Communication (QWC) is fine here. There are a few minor inconsistencies with grammatical correctness, possibly through being rushed to finish the question of a simple slip of the mind, e.g. - "Powell and Miklowitz carried out a meta-analysis found a link between frontal lobe damage and depression", which omits "and". These are not hugely pressing errors, but frequent grammatical errors like this are likely to lower the QWC mark. The candidate should also consider their wording a little more carefully, particularly when using psychological terminology, e.g. "makes you unable to resist stressors" - this sounds like the description of an addiction, as if depressed patients are addicted to stress-inducing stimuli,so just be careful with your phraseology. Instead, you could write "makes people more susceptible to anxiety from stressors".

Level of analysis

The Level of Analysis here is fair, though far from perfect. Each point is well-focused and pertains to the question proposed. Each study is a good example of psychological research into the biological explanation of an affective disorder, though a lot more could be done in terms of evaluation. The knowledge shown is extensive and very rarely inaccurate, but the lack of evaluation is where this essay struggles to gain the high grade the candidate would be looking for as there is very little of it, despite there being a great deal of knowledge shown. Assuming the 8 marks are assigned for AO1 (knowledge and understanding) and the 16 marks for AO2 (evaluation), this essay can expect to receive roughly 8/8 + 2/16, a total of 10/24, which is about 42% and therefore a low C grade. The knowledge shown in the essay suggests better could be achieved were the evaluation of a sufficient standard. As it stands, only two very brief, non-contextualised points are made. I would recommend therefore that the candidate draw back the extensive writing of the knowledge and aim to write down the bare minimum of the biological evidence/theories and then evaluate with a far more detailed approach - remember, the question directs you to "Outline" and then "Evaluate". To outline is to briefly describe - not much of the same level of detail is needed when asked to "Outline". Time management is also important; at least one evaluative point in conjunction with each theory should take candidates about six minutes each, totalling twenty-four minutes spent on the question in total, including five minutes planning time.

Response to question

The candidate here has structured there answer fairly well, if a little too prescriptively. Nonetheless, it forms a cohesive and coherent essay that tackles the question well. There are two pieces of evidence that support the biological explanation of depression and two that refute the explanation for such an affective disorder; this helps balance the essay and shows a candidate who has a wide knowledge of psychological research and how it can fortify an answer. I would perhaps encourage candidates to name the authors of the studies they are citing in their essays, thought this is not an absolute necessity. Elsewhere, there does not appear to be a great deal of evaluation evident. Evaluation is an important part of the mark scheme and up to 16 marks are awarded for it. It is therefore required of candidates that explicit evaluative points are made. In this answer, these points are rare, and when they are made they are not sufficiently supported nor contextualised (more on this in Level of Analysis).

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