Genetic Explanation for OCD Flashcards
1
Q
What are candidate genes?
A
- OCD is inherited through the genetic tansmission of a specific gene (candidate genes) from our parents
- OCD Candidate genes are specific genes that lead to a vulnerability to OCD
- 5HTT gene is responsible for the transportation of seratonin in a neuron
- Inheriting a faulty 5HTT gene disrupts seratonin transportation leading to low levels in the synapse
- In 2003 Ozaki et al found a mutation of the 5HTT gene in families where 6 out of 7 members had OCD
2
Q
What is polygenic?
A
- However, other researchers believe that OCD is too complex to be caused by just one gene - OCD must be a polygenic disorder
- Taylor did a meta-analysis and found evidence of up to 230 different genes involved in OCD
3
Q
How is twin studies a strength?
A
- A strength of the genetic explanation is that they have supporting evidence from twin studies
- Nestadt et al reviewed twin studies into OCD and found a 68% concordance rate for MZ twins and a 31% for DZ twins
- As the proportion of shared genes increases from DZ (50%) to MZ (100%) twins so does the likelihood of both twins having OCD
- This shows that OCD develops due to genetic factors and is inherited
- This validates the genetic explanation
4
Q
How does the diathesis stress model weaken the theory?
A
- A weakness of the genetic explanation is that it is too simplistic as the diathesis stress model may be a better explanation
- The model argues that certain genes make someone more vulnerable to OCD but an environmental trigger (stressor) needs to happen for OCD to actually develop
- Cromer et al found that over half of OCD patients had experienced something traumatic in their past and that OCD was more severe in those with more than one trauma
- This shows that OCD is not entirely genetic as traumatic events play a key role too - to understand OCD we must take a holistic approach considering both environment and genetics
- As the genetic explanation doesn’t do this it is incomplete and reduces in validity
