Psychopathology - The biological approach to explaining OCD Flashcards
What does the genetic explanation for OCD focus on?
Focus on identifying specific candidate genes involved in OCD
OCD is believed to be a polygenic condition, what does this mean?
There is not just one gene that is responsible for its development but many genes that contribute to it. Taylor (2003) suggests that as many as 230 genes may be involved in the condition.
What are two examples of genes that have been linked to OCD?
COMT Gene - Catechol-O-methyltransferase
SERT Gene - Serotonin
What is the COMT neurotransmitter’s role in explaining OCD
1 particular variation of this gene results in higher levels of dopamine and this variation is more common in patients with OCD, compared to people without OCD.
What is the SERT gene’s role in explaining OCD?
Affects the transport of the neurotransmitter serotonin. Transportation issues cause lower levels of serotonin to be active within the brain and are associated with OCD.
What is the Diathesis-Stress Model?
Genes produce a vulnerability to certain disorders rather than producing the disorder itself. Certain environmental stresses such as the death of a loved one or stress at work would then trigger the condition in those that have the vulnerability.
What neurotransmitters are believed to play a role in OCD?
Serotonin and Dopamine
What are neural explanations of OCD related to?
Abnormal brain circuits in various regions of the frontal lobes of patients with OCD
What is the orbitofrontal cortex’s role in OCD?
The orbitofrontal cortex relays information about things that are worrying / risky which are sent from different parts of the brain and then converts those emotions into actions. PET scans have showed higher activity in the OFC in patients with OCD when, example, asked to hold a dirty item i.e Germ Hazard
What are the strengths of genetic make up causing a vulnerability to OCD?
One of the best sources of evidence for the importance of genes is twin studies. Nestadt et al. (2010) reviewed previous twin studies and found that 68% of identical twins shared OCD as opposed to 31% of non-identical twins.
Strongly suggests a genetic influence on OCD.
What are the strengths of the Diathesis stress model theory?
Cromer et al. (2007) found that over half the OCD patient in their sample had a traumatic event in the past and that OCD was more severe in patients with more than one trauma.
This suggests that OCD may not be entirely genetic in origin, or at least not in all cases.
What is a limitation of the biological explanation for OCD?
There is an issue with understanding neural mechanisms involved in OCD. While there is evidence which suggest that certain neural systems do not function normally in patients suffering from OCD, such as the orbitofrontal cortex, research has also identified other areas of the brain that are occasionally involved as well.
This means that there is no brain system which has consistently been found to play a role in OCD.
Although there is evidence that neurotransmitters and brain structures are implicated, it must not be concluded that there is a cause and effect relationship since it is difficult to ascertain whether the biological abnormalities seen are a cause of OCD or the result of the disorder.
