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Flashcards in Genetic causes of OCD Deck (9)
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COMT gene

- Genes can be the main cause of OCD as OCD might be inherited whereby sufferers have a genetic vulnerability to get the illness.
- Psychologists use family or twin studies to investigate genetics.
- OCD is polygenic as
one single gene is not responsible for the disorder. Instead, many genes might be responsible for causing OCD and these are known as candidate genes.
- COMT gene regulates production of neurotransmitter dopamine, where high levels of it is associated with OCD.
- COMT gene is more common in OCD patients.


SERT gene

- Affects the transportation of serotonin which results in low levels of serotonin which leads to low mood and depressive symptoms.
- SERT gene is on chromosome 17 and a mutation of this gene can cause OCD.
- Research conducted by psychologists shows that 6/7 family members who has OCD has a mutation of SERT gene.


Strength: Research support

- Nestadt (2000) found that people who had a first degree relative who already had OCD were five times more likely to get the illness.
- Billett (1998) found that from a meta-analysis of 14 twin studies that OCD is twice more likely to be concordant in identical monozygotic twins than dizygotic.


Weakness: Concordance rate

- The concordance rate for OCD is not 100% so OCD cannot be caused entirely by genetic factors.
- Genetic explanation fails to take into account psychological and environmental factors.


Weakness: Behavioural approach

- Behavioural approach contradicts the genetic explanation for OCD.
- The Two Process Model suggests that OCD can be learnt via classical conditioning and then maintained via operant.
- Behavioural approach has gained a lot of support in explaining the cause of OCD as behavioural therapies such as Exposure is used to treat OCD.


Research by Beekman and Cath

- Meta analysis was conducted of twin studies into OCD that occurred over the last 70 years.
- MZ twins were compared against DZ twins.
- 10,034 twin pairs were studies overall.
- The results found that in children, OCD is inherited via genes and the genetic influence ranges from 45-65%.
- In adults, OCD is inherited via genes and the genetic influence ranges from 27-47%.
- Conclusion that OCD is transmitted genetically but it's more apparent in children.


Weakness Beekman and Cath: Controlled condition

- Research can be criticised as majority of twin studies were not performed in controlled conditions.
- The data is not very objective or scientific which may affect the validity and reliability of results.


Weakness Beekman and Cath: Gene mapping

- Gene mapping was not taken into consideration.
- Gene mapping would look close at DNA of the twins that had OCD and compare this with twins that don't.
- Comparisons need to be made for the results to be more valid.


Strength Beekman and Cath: Long period

- Determines that a cause of OCD to be genetic in childhood and adulthood and the data was retrieved from a long period of time.