the biological approach to explaining ocd Flashcards
genetic explanation
lewis 1936
observed the of his ocd patients 37% had parents with ocd and 21% had siblings with ocd. this suggests that ocd runs in families ,although it being passed it is not based on a gene but genetic vunerbality .
genetic explanation
diathesis stress model
according not this certain genes leave some people more likely to suffer a mental disorder but it is not certain , some environmental stress is neccesray to trigger the condition
genetic explanation
candidate genes
genes that create vuenrabilty to ocd = candidate genes
some of these genes are involved ins regulating the development of the serotonin system .
genetic explanation
ocd îs polygentic
polygentic = ocd is not caused by one gene but several are involved
- Taylor 2013
analysed findings of previous studies and found evidence that up to 230 different genes may be involved in ocd.
genes that have been studied in relation to ocd include those associated with the action of dopamine as well as serotonin both neurotransmitters believed to have a role in regulating mood .
genetic explanation
différent types of ocd
one group of genes may cause ocd in one person but a different group of genes may cause the disorder in a another person . the term for this is etiologically heterogeneous meaning the origin of ocd has different causes.
there is also some eveience to suggest that diffrent types of ocd may be the result of particular genetic variations such as hoarding disorders and religious obsessions.
genetic explanation, a strength
good supporting evidence
there is evidencefrom a variety of sources for the idea that some people are vuenrbale to ocd as a result of they genetic makeup
one of the best sources of obedience 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
this strongly suggests a genetic influence on ocd
genetic explanation, limitation
too many candidate genes
although twin studies strongly suggest that ocd is largely under genetic control psychologists have been much less successful at pinning down all the genes involved . one reason for this is because it appears several genes are involved and the each genetic variation only increases the risk of ocd by a fraction.
the consequence is that a genetic explanation is unlikely to ever be useful because it provides little predictive value
genetic explanation, limitation
environmental risk factors
environmental risk factors can also trigger or increase the risk of developing ocd
- cromer et al 2007
found that over half the ocd patients in their sample had a traumatic event in the past ad that ocd was more severe in those that had more then one trauma
this suggests that ocd cannot be entirely genetic in origin at least not in all cases , it may be more productive to focus one the environmental cause because we are more able to do something about these
neural explanations
the role of serotonin
neurotransmitters are responsible for relaying information from one neuron to another. if a person has low levels of serotonin then normal transmission of mood relevant info does not take place , and sometimes other relevant mental processes .
- at least some cases of ocd may be explained by a reduction in the functioning the serotonin system in the brain.
neural explanations
decision making systems
some case of OCD in particular hoarding disorder seem to be associated with impaired descion making. in turn may be associated with abnormal functioning of the lateral slides and the frontal lobes of the brain. frontal lobe =n responsible for logical thinking and descion making
also evidence to suggest that an area called the left parahippocampal gyrus associated with processing unpleasant emotions functions abnormally in OCD.
neural explanations, a strength
some supporting evidence
role of neural mechanisms in OCD is supported by antidepressants that work purely on serotonin system . increasing levels of this neurotransmitter is effective in relieving symptoms of OCD . suggesting serotonin systems are involved in OCD.
NESTASDT ET AL 2010
OCD forms apart of a number of other conditions that ar biological in origin ie Parkinson’s disease
- suggests that the biological processes that cause the symptoms in this cons may also be responsible for ocd
neural explanations , a limtiation
unclear what neural mechanisms are involved
CAVEDINI ET AL 2002
shows that these neural systems are the same systems that function abnormally in ocd
however research has identified other Brian systems that may be involved sometimes but no system has been found that always plays a role in ocd
- cannot really claim to understand the neural mechanism involve in ocd
neural explanations , a limtiation
should not assume the neural mechanism cause OCD
no evidence to suggest that various neurotransmitters and structures of the brain do not function normally in patients with ocd .
however this is not the same as saying that the abnormal functioning causes the ocd.
- biological abnormalities could be a result of ocd rather then its cause
