OCD Explanation

Question 1

Two types of explanations

Answer 1

Genetic and Neural

Question 2

Genetic Explanation

Answer 2

Genes, Candidate Genes, OCD is Polygenic, Different types of OCD.

Question 3

Genes

Answer 3

Genes are involved in the vulnerability to OCD. Lewis (1936) found 37% of OCD patients had parents with OCD and 21% had siblings with it. Suggests genetic vulnerability is passed down.
Stress-diathesis model states certain genes leave some people more likely to develop a mental disorder, but this needs to be triggered by a stressor.

Question 4

Candidate Genes

Answer 4

These create vulnerability for OCD. Some of these are involved in regulating the development of the serotonin system.

Question 5

OCD is Polygenic

Answer 5

A combination of genetic variations significantly increase the vulnerability.
Taylor (2013) up to 230 genes involved. These are often associated with actioning dopamine and serotonin.

Question 6

Different Types of OCD

Answer 6

Aetiologically heterogeneous so for each person a different group of genes cause it. Also evidence to suggest different types of OCD may be result of particular genetic variations like hoarding disorder.

Question 7

(G) Strength

Answer 7

Strong evidence.
Nestadt et al (2010) reviewed twin studies and found 68% of monozygotic twins shared OCD but only 31% of dizygotic.
Must be some genetic link between within the DNA as monozygotic twins have the same DNA.
Furthermore… research found if a family member has OCD they are 4 times more likely to develop it so there must be a genetic link.
However… candidate genes are very difficult to find in humans and so we do not know the role they play which decreases validity.

Question 8

(G) Weakness (E)

Answer 8

There are environmental risk factors.
Cromer et al (2007) found over half his OCD patients had experienced a traumatic event and where the OCD was more severe they had a worse or more traumatic experiences.
Trauma can affect a person’s susceptibility. Shows how OCD is not just genetic vulnerability and that maybe nurture also has a role.
Furthermore… this may suggest that a fully biological explanation is not accurate and that maybe a different approach should be used, like the stress-diathesis model argues someone has a genetic vulnerability (candidate genes) and then an environmental trigger (trauma) results in the development. This means that nature and nurture intertwine (interactionist)

Question 9

Neural Explanation

Answer 9

Role of serotonin and Decision-making symptoms

Question 10

Role of Serotonin

Answer 10

Serotonin is a neurotransmitter believed to help regulate mood. It relays information from one neuron to the other about mood. If low then the transmission of mood-relevant information does not take place and so feel low moods. Some cases of OCD can be explained by a reduction in the functioning of the serotonin system.

Question 11

Decision-making Symptoms

Answer 11

Some cases are linked to impaired decision thinking which is associated with the abnormal functioning of the lateral and frontal lobe responsible for logical thinking and decision-making. Also evidence to suggest the left parahippocampal gyrus functions abnormally in OCD patients associated with processing unpleasant emotions.

Question 12

(N) Strength

Answer 12

Supportive evidence.
Anti-depressants work by increasing the amount of serotonin in their system and have been found to successfully relieve the symptoms of patients with OCD.
Serotonin abnormalities do in fact influence OCD and that this knowledge has had practical application to helping people with OCD by providing an effective treatment.
Furthermore… symptoms related to OCD form part of other conditions known to have a biological origin like Parkinson so we can assume that biological processes underlie OCD also. This gives greater validity.

Question 13

(N) Weakness (W)

Answer 13

Not clear which neural mechanisms are involved.
Studies have identified other brain system, alongside neurotransmitters, that are sometimes involved by no system has always been found in OCD.
They cannot claim which ones involved as there are no consistent once which decreases validity.
Furthermore… the link between OCD and serotonin may not be related to OCD but depression as most people with OCD suffer from depression which is also known to disrupt serotonin levels. This means this co-morbidity may be affecting our understanding.
Furthermore… this is only correlational so we don’t know if these abnormalities are causing OCD or the result of it. As well as if there is a third unknown variable causing all this. This would mean the true explanation for OCD would be unknown.