Psychopathology : Explaining OCD Flashcards
What does the genetic explanation suggest about OCD?
> OCD has a genetic basis, meaning it is at least partially inherited.
OCD is said to be polygenic, meaning there are multiple candidate genes (genes known to be linked to OCD)
OCD can be caused by different combinations of candidate genes.
What are the specific types of candidate genes?
> SERT = this gene is understood to cause abnormally low levels of the neurotransmitter serotonin.
COMT = this gene helps regulate the levels of the neurotransmitter dopamine, one form of the gene can lead to higher levels of dopamine.
Explain the diathesis stress models role in the genetic explanation.
> Genetics do play a role in development of OCD, but cannot alone explain it.
According to the diathesis stress model, candidate genes act as a diathesis (meaning they cause vulnerability).
However, in order for a vulnerable individual to develop OCD, they must also be exposed to environmental stressors that interact with the diathesis to trigger the onset of OCD.
Thus, OCD can only develop if a person has genetic vulnerability and sufficient stress.
What is the Neural explanation?
> The neural explanation considers the nervous system in causing OCD : the brain and neurotransmitters.
The Prefrontal cortex is a type of biological structure in the brain which links to OCD symptoms. — it’s involved in decision making, eg deciding to wash your hands.
Serotonin is a type of neurotransmitter linked to OCD, as patients with OCD have been found to have abnormally low levels of serotonin. — serotonin regulates mood, thus this could link to emotional characteristics.
Dopamine is another type of neurotransmitter linked to OCD, as patients with OCD have been found to have abnormally high levels of dopamine. Dopamine has an excitatory function , thus explaining the hyperactivity of the PFC in the brain of people with OCD.
What is a limitation of the Biological Explanation of OCD?
It often relies on correlational research. Numerous studies have found an association between OCD and biological abnormalities, like low levels of serotonin or the presence of a particular gene. However, correlation does not show causation. Just because researchers have found a particular biological feature is associated with OCD, doesn’t mean this biological feature causes OCD. For example. It could be that having OCD might cause low levels of serotonin rather than low levels of serotonin causing OCD. On the contrary, the uncertain direction of causation doesn’t apply to correlation between candidate genes and OCD. This is incorrect as we have our genes from conception and OCD develops later, so OCD can’t cause a person to have a gene. Thus, the limitation of correlational research is that it may weaken the biological explanation of OCD.
What research support is there for the biological approach’s genetic explanation of OCD?
Nestadt (2010) reviewed previous twin studies and found that 68% of identical twins shared OCD as opposed to 31% of non identical twins. If OCD was not genetic, then we would expect the concordance rates for identical twins and non identical twins to be similar. The relative high concordance rates for identical twins therefore provide supporting evidence for one component of the biological explanation of OCD: the genetic explanation. Moreover, the fact that the concordance rates for identical twins isn’t 100% suggests the environment also plays a casual role in OCD, as were the condition entirely genetic. Then the identical genes of identical twins would result in 100% concordance. Therefore, this provides support for the diathesis stress model, as OCD has a genetic and an environmental component. However, this research could be criticised for its lack of validity, as twin studies rely on the assumption that identical and non identical twins have the same shared environment. But it could be argued that identical and non identical twins don’t have the same level of shared environment as identical twins look identical therefore may be treated more similarly. If true, it’s not possible to say whether the shared genes or the shared environments of identical twins cause their concordance rates for OCD to be higher.
What research support is there for the biological approaches neural explanation of OCD?
For example , Soomro (2009) reviewed studies comparing the effectiveness of SSRIs to placebos in the treatment of OCD. All 17 studies reviewed showed that SSRIs were significantly more effective in treating OCD than placebos. Soomros research supports the neural explanation because SSRIs work by increasing levels of the neurotransmitter serotonin in the brain. If this research is correct there must be a neural component to the disorder, meaning the biological approaches neural explanation of OCD must be correct. Furthermore, this research illustrates the real life applications of the neural explanation. The value of the neural explanation is it has informed the development of treatments for OCD. Without a valid supporting explanation, these treatments may not have been developed. Moreover, the fact that this research comes from a review of published studies strengthens its conclusions on the neural explanation. Because reviews consider the results of multiple studies, they combine multiple samples together, giving an overall review giving SSRIs strong population validity.
