The Biological Approach to Explaining OCD Flashcards
What is a candidate gene?
Specific genes which create a vulnerability for a mental disorder
What are two types of genes shown to be a candidate gene to OCD?
- Serotonin genes
- Dopamine genes
What are serotonin genes?
Implanted in the transmission of serotonin across synapses
What is an example of a serotonin gene?
5HT1-D beta
What does serotonin and dopamine regulate?
Mood
What does it mean by calling OCD polygenic?
OCD is not caused by one single gene but several genes involved
What did Taylor (2013) find about OCD and being polygenic?
The are 230 different genes that may be involved in OCD
What does the COMT gene do?
Helps reduce the action of dopamine
What does the SERT gene do?
Affects the transport of serotonin
What does the diathesis-stress model suggest about OCD?
People gain a vulnerability towards OCD through genes but an environmental stressor is also required
What is aetiologically heterogeneous?
One group of genes may cause OCD in one person but in a different person it may be caused a different group of genes
Are levels of serotonin higher or lower in those suffering from OCD?
Lower
Are levels of dopamine higher or lower in those suffering from OCD?
Higher
What is dysfunctional about people with OCD?
- Frontal lobe
- Parahippocampal gyrus
What is the frontal lobe responsible for?
Logical thinking and making decisions
What is the left parahippocampal gyrus responsible for?
Processing unpleasant emotions
Is there supporting evidence the genetic explanation?
Yes
What is a good study to show the effect of genes?
Twin studies
What did Nestadt et al (2010) find?
68% of identical twin shared OCD opposed to the 31% of non-identical twins
What is the limitations of twins studies?
- Environment may have actually caused disorder
- Observing and imitating the behaviour
- Difficult to untangle effects of environment and genetics factors
What is the problem with candidate genes?
- Too many genes involved
- Not successful at pinning down all the genes involved
- Genetic variation only increases the risk of OCD by a fraction
What did Cromer et al (2007) find?
Over half of their sample had a traumatic event in the past and had a more sever OCD
Why is the neural explanation good for practical application?
Allows medication to be developed which helps sufferers
Why may the serotonin-OCD link not be as unique as believed?
Those with OCD become depressed (co-morbidity)
