OCD: Bio Explanations

Question 1

What is a genetic explanation

Answer 1

Suggestion that behavior can be inherited through genetic transmission.

Question 2

What is Co-morbidity

Answer 2

When two or more disorders are likely to be present together, such as OCD and depression

Question 3

What is serotonin

Answer 3

A neurotransmitter implicated in OCD

Question 4

What is the definition of Polygenic

Answer 4

Where more than one gene contributes to a disorder

Question 5

What is a Neural explanation?

Answer 5

It is when there is an abnormal level of neurotransmitters and damaged regions of the brain.

Question 6

What are Hereditary differences?

Answer 6

When the disorder is passed through genetic transmission.

Question 7

What is the SERT gene

Answer 7

The SERT gene is linked to the neurotransmitter serotonin and affects the transport of the serotonin (hence SERotonin Transporter), causing lower levels of serotonin which is also associated with OCD (and depression)

Question 8

What is the COMT gene?

Answer 8

The COMT gene is associated with the production of catechol‐O‐methyltransferase, which regulates the neurotransmitter dopamine. One variation of the COMT gene results in higher levels of dopamine and this variation is more common in patients with OCD, in comparison to people without OCD.

Question 9

Taylor (2013) research into polygenic

Answer 9

Researcher Taylor (2013) had analysed findings of previous studies (meta- analysis) and found evidence that there may be up to 230 genes involved in OCD.

Genes that have been studied in relation to OCD include those associated with the action of dopamine as well as serotonin as both are believed to have a role in regulating mood.

Question 10

Genetic Explanations of OCD: Research into families

Answer 10

Lewis (1936) observed that of his OCD patients, 37% had parents with OCD and 21% had siblings with OCD.

This suggests that OCD runs in families (higher concordance rates with first-degree relatives), although what is passed on from one generation to the next is genetic vulnerability, not the certainty of OCD.

Question 11

Strength: Research Support into OCD as a genetic basis

Answer 11

P: A strength of the biological explanations for OCD is that there is research support to suggest that it has a genetic basis.

E: This comes from twin studies. Nestadt et al (2010) found that 68% of identical twins shared OCD as opposed to 31% of non-identical twins.

C: This strongly supports a genetic influence on OCD.

Counterargument: However, no twin study has found a concordance rate of 100% in identical twins, which means that biological factors are not the only factor contributing to OCD and there must be environmental factors
which also contribute to this disorder.

Question 12

Limitation to OCD research, too many candidate genes?

Answer 12

P: A limitation of the genetic explanation is that there are too many candidate genes to distinguish the cause of OCD.

E: Twin studies may suggest that OCD is largely
under genetic control, but psychologists haven’t been so successful at pinning down all of the genes involved. This may be because several genes are involved, and that each genetic variation only increases the risk of OCD by a fraction.

C: Therefore, this explanation is unlikely to be useful as it provides little predictive evidence.

Question 13

How does the neural structure of the basal ganglia link to OCD?

Answer 13

Brain structure involved in coordination of movement

Patients with injuries to this region experience OCD esq symptoms

Max et al (1994) found that when basal ganglia disconnected via surgery, symptoms are reduced

Question 14

Serotonin and dopamine’s link to OCD

Answer 14

Serotonin regulates mood and lower levels of our associated with mood disorders and depression some cases of OCD are also associated with this
higher levels of dopamine are associated with some of the symptoms of OCD in particular the compulsive behaviours