Psychopathology - Biological explanations of OCD

Question 1

what are the two types of biological explanations for OCD

Answer 1

• Genetic
• neural

Question 2

give 3 genetic explanations for OCD

Answer 2

• candidate genes
• OCD is polygenic
• there are different types of OCD

Question 3

Explain candidate genes as an explanation for OCD

Answer 3

researchers have identified genes, which create vunerability for OCD, called candidate genes. Some of these genes are involved in regulating the development of the serotonin system. e.g. the gene 5HT1-D beta is implicated in the efficiency of transport of serotonin across synapses

Question 4

Explain OCD being polygenic as an explanation for OCD

Answer 4

• like many conditions, OCD seems to be polygenic. This means that OCD is not caused by one single gene but that several are involved.
• Taylor 2013 found evidence when analysing other studies that up to 230 different genes may be involved in OCD.
• Genes that have been studied in relation to OCD include those associated with the action of dopamine and serotonin both neurotransmitters believed to have a role in regulating mood.

Question 5

explain how there being different types of OCD is an explanation for OCD

Answer 5

One group of genes may cause OCD in one person but a different group of genes may cause the disorder in another person. The term use to describe this is aetiologically heterogeneous.
There is also some evidence to suggest that different tyes of OCD may be the result of particular genetic variations, such as hoarding and religious obsession.

Question 6

define aetiologically heterogeneous

Answer 6

the origin (aetiology) of OCD has different causes (heterogeneous

e.g. OCD is aetiologically heterogeneous, meaning different combinations of genes cause different types of OCD in different people.

Question 7

Give a strength of the biological explanations

Answer 7

There is good supporting evidence

Question 8

Explain how good supporting evidence is a strength of the biological explanation of OCD

Answer 8

There is evidence from a variety of sources for the idea that some people are vulnerable to OCD as a result of their genetic make-up. One source of evidence for the importance of genes is twin studies. Nestadt et al 2010 reviewd pervious twin studies and found that 68% of identical twins shared OCD as opposed to 31% of non-identical twins. This strongly suggests a genetic influence.

Question 9

Evaluate Nestadt et al 2010 in supporting the biological explanations for OCD

Answer 9

A weakness is that the concordance rate should have 100% in MZ twins if it was solely genetics, but it is not which suggests that there must be other factors that cause OCD.
A strength is that the concordance rate of identical twins was over double that of non-identical twins this is a strength because it suggests that genetics does have a role in OCD this means that the biological explanation is to some extent accurate.

Question 10

what is a limitation of twin studies

particularly in relation to Nestadt et al 2010

Answer 10

Ignores environmental factors, although twin studies are used as there is a greater genetic link, these twins also share the same environment, which could trigger OCD.
There is evidence to suggest that identical twins are treated ‘more similar’ in terms of their environment, (e.g. expectations, style of dress, extracurricular activities) than non-identical twins who are treated more as individuals.

Question 11

Evaluate candidate genes as an explanation for OCD

Answer 11

• A weakness is that there are too many genes involved. This is a weakness because psychologists have not been successful at pinning down all the genes involved. This means that we cannot be confident in this as an explanation on its own.

Question 12

Evaluate OCD being aetoologically heterogeneous as an explanation for OCD

Answer 12

A weakness is that each genetic variation only increases the risk of OCD by a fraction this is a weakness because it suggests that genes are not the sole cause of OCD. This means that this cannot be the only explanation for OCD

Question 13

explain environmental factors as an alternative explanation for OCD

Answer 13

• Individuals may gain a vulnerability towards OCD through genes that is then triggers by an environmental stressor.
• Cromer (2007) found that over half of the OCD patients in their sample had a traumatic event in the past and that OCD was more severe in those with more than one trauma.
• This means that it may be more productive to focus on environmental causes as it seems OCD is not entirely genetic in origin.

Question 14

Give 2 neural explanations of OCD

Answer 14

role of neurotransmitters
abnormal functioning of the frontal lobes

Question 15

explain the role of neurotransmitters in OCD

Answer 15

An explanation of OCD is concerned with the role of th eneurotransmitter serotonin, which iss thought to regulate mood. Neurotransmitters are responsible for relaying information from one neuron to another. If a person has low levels of serotonin normal transmittions of mood relevant information does not take place and mood is affected.

Question 16

explain abnormal functioning of the frontal lobes as an explanation of OCD

Answer 16

Some cases of OCD particularly hoarding disorder, seem to be associated with impaired decision making. This in turn may be associated with abnormal functioning of frontal lobes of the brain. The frontal lobes are resobnsible from decision making and logical decisions

Question 17

evaluate low levels of serotonin as an explanation for OCD

Answer 17

A strength is that antidepressants such as SSRIs, which are used to control levels of serotonin, are seen to be effective in reducing OCD symptoms, which would support the idea of an imbalanced neural network.
A weakness is that Not all OCD sufferers respond positively to antidepressants ( serotonin levelers), which would show it is not the neural network causing OCD in those patients.