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Model Answer for Question 10 Paper 2: AS Psychology, June 2016 (AQA)

AS, A-Level

Last updated 14 May 2017

Section B - Psychopathology

10 Two students were discussing their friend David who has recently been diagnosed with obsessive-compulsive disorder (OCD).

Melanie says, “It wasn’t a surprise to me that David has OCD because his mum is always tidying things, putting them in order and checking switches”.

Emma says, “Really, I didn’t know that. I always thought that people with OCD have something in their brains that makes them behave in that way”.

Outline and evaluate neural and genetic explanations of obsessive-compulsive disorder. Refer to the conversation above in your answer. [12 marks]

The following answer was written by Patrick as Buttershaw Business and Enterprise College in May 2016. It received 12/12: The genetic explanation for obsessive-compulsive disorder (OCD) includes two genes the COMT and the SERT genes. The COMT gene is involved in the regulation of dopamine in the brain. Dopamine is an excitatory neurotransmitter and has been linked to OCD when in higher levels. The COMT gene, when mutated, does not regulate the dopamine as well as it should, this means levels rise, and high levels of dopamine can cause OCD. The SERT gene is involved in the transportation of serotonin, an inhibitory neurotransmitter. When levels of serotonin are low, a person is more likely to get OCD. The SERT gene if mutated reduces serotonin levels to lower than they should be, which causes a person to be more likely to get OCD. Melanie is saying that David inherited one or both of these genes from his mother, causing him to have OCD.

The neural explanation for OCD includes the ‘worry circuit’, in the brain. The two main areas of the brain associated with OCD are the Orbit Frontal Cortex and the caudate nucleus. The OFC is responsible for sending the worry signals, which are picked up by the thalamus and directed around the body. The caudate nucleus is responsible for suppressing some of these worry signals. If the caudate nucleus is not working properly, the worry signals do not get surprised, and a person worries too much this cab cause OCD. Emma is also right in saying that it is something in someone’s brain that causes OCD both can be used to explain OCD.

A strength of the genetic explanation for OCD is that research was done by Choy et al. shows that serotonin can cause OCD at low levels. Choy tested SSRI’s, a type of drug that blocks the reuptake of serotonin, and found that they were successful in most patients, this shows that low levels of serotonin are linked with OCD. Therefore a strength of the genetic explanation to explain OCD is that there is supporting research which highlights the implication of serotonin in the development of OCD.

A further strength of the explanations is that there is research that says that OCD can be inherited through genes. Soomro studied people with OCD and their family members and found that if a first generation relative had OCD, an individual is five times more likely to get it at some point in their lives, than if a relative did not have it. This supports the genetic explanation and suggests that OCD runs in the family.

However, a limitation of the genetic explanation is that not everyone with these genes has OCD. This means that there must be other factors that can cause or contribute to an individual getting OCD (e.g. environmental influences such as a negative experience with hygiene and becoming sick). Therefore, a limitation of the genic explanation for OCD is that it does not take other factors (environmental) into account and other psychologists (e.g. behaviourists) would argue that OCD is a learnt condition.

Exam Hint: Some students failed to considered neural and genetic explanations and referred to cognitive explanations (related to Emma’s ‘thinking’). While there are cognitive explanations of OCD this is odd given the nature of the question and the specification requirements.

Some answers failed to acknowledge the STEM which costs students important application marks. However, the most common error/confusion was over the role of the COMT and SERT gene and whether serotonin increases/decreases. Finally, some students evaluated the biological approach generally and failed to apply their evaluation to the question and psychopathology. 

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