The biological approach to explaining OCD

Question 1

What is the biological approach?

Answer 1

A perspective that emphasises the importance of the physical processes

Question 2

What are genetic explanations?

Answer 2

Genes make up chromosomes and consists of DNA which codes the physical features and psychological features

Question 3

What are neural explanations?

Answer 3

The nervous system brain and individual neurons

Question 4

What is the type of biological explanation used to explain OCD?

Answer 4

Genetics - genes are involved in the vulnerability to OCD

Question 5

What was the research into the genetics of OCD?

Answer 5

Lewis (1936) found that of OCD patients 37% had parents with the disorder and 21% of siblings this suggests that it runs in families

Question 6

What does the diathesis stress model state?

Answer 6

Certain genes leave certain people more vulnerable but it is not a certainty - some environmental stress may trigger the condition

Question 7

What re candidate genes?

Answer 7

These are genes which creates the vulnerability. Some of these genes are important in the development of the serotonin system. 5HT-D beta gene is implicated in the efficiency of transport of serotonin across synapses

Question 8

What is meant by ‘OCD is polygenic’

Answer 8

This means that one gene is not responsible but several are involved. Taylor (2013) has analysed findings from previous studies and found evidence that 320 genes may be involved.

Question 9

What types of genes are especially studied?

Answer 9

Genes associated with the action of dopamine as well as serotonin as they are both neurotransmitters that regulate mood

Question 10

How are there different types of OCD?

Answer 10

One group of genes may be associated with OCD in one person but not in another who may suffer as a result of a different set of genes- this is known as aetiologically heterogenous meaning the origin of OCD is due to different causes

Question 11

What are the neural explanations?

Answer 11

Genes associated with OCD are likely to affect the key neurotransmitters as well as structures of the brain

Question 12

What is the role of serotonin?

Answer 12

If a person has a lower level of serotonin than normal transmission of mood-relevant information does not take place so mood and sometimes other mental processes are affected so some cases may be explained by reduction in the functioning of serotonin system in the brain

Question 13

What is the impact of the decision making systems?

Answer 13

Some cases of OCD and particularly hoarding disorder seem to be associated with impaired decision making and this in turn may be associated with abnormal function of the frontal lobe of the brain

Question 14

What is the frontal-lobe?

Answer 14

It’s at the front of the brain and is responsible for logical thinking and decision making

Question 15

What other area of the brain is there evidence for having an affect on OCD?

Answer 15

The left para hippocampul gyrus associated with procession plus emotional function abnormality and OCD

Question 16

How is there good supporting evidence?

Answer 16

There is evidence from a variety of sources that suggest that some people are vulnerable to OCD as a result of their genetic makeup - one of the best sources are twin studies
Nest act et al (2010) reviewed previous twin studies and found that 68% of identical twins shared OCD as opposed to 31% of non-identical twins which strongly suggests a genetic influence on OCD

Question 17

What is meant by too many candidate genes?

Answer 17

Psychologists haven’t been successful in pinning down all the genes involved in OCD and this is because it appears many genes are involved and each genetic variation only increases the risk of OCD by a fraction and this means that a genetic explanation is unlikely to ever be very useful because It provides very little predicted value

Question 18

What are the environmental risk factors?

Answer 18

They can also trigger or increase the risk of developing OCD
Chroma et al (2007) found that over half the OCD patients in their sample had a traumatic event in their past which suggests that OCD cant be entirely genetic in origin

Question 19

How is there some supporting evidence for the role of neural mechanisms in OCD ?

Answer 19

Antidepressants work purely on the serotonin system, increasing levels of this neurotransmitter - such drugs are effective in reducing OCD symptoms and this suggests that the serotonin system is involved in OCD

Question 20

What do OCD symptoms also form part of?

Answer 20

A number of other conditions that are biological in origin e.g. parkinsons disease which suggests that the biological process that cause the symptoms in those conditions may be responsible for OCD

Question 21

Why is it not clear what neural mechanisms are involved?

Answer 21

Studies of decision making have shown that these systems that function abnormally in OCD
However other research has also identified other brain systems that may be involved but no one system has been found to always play a role in OCD suggesting we don’t fully understand the neural mechanisms

Question 22

What is meant by we should not assume the neural mechanisms in OCD?

Answer 22

There is evidence to suggest that various neurotransmitters and structures of the brain do not function normally in patients with OCD however this isn’t the same as saying that abnormal functioning causes OCD as biological abnormalities could be as a result of not as a cause

Question 23

Why are twin studies flawed as genetic evidence?

Answer 23

They make the assumption that identical twins are only more that non-identical twins in terms of genes but they overlook the fact that identical twins share the same environment

Question 24

How might the serotonin OCD link be comorbidity with depression?

Answer 24

Many people who suffer OCD become depressed - having 2 disorders together is called comorbidity. This depression may disrupt the serotonin system so it could be that the serotonin is disrupted in many patients with OCD because they are depressed as aswell