The biological approach to explaining OCD Flashcards
What does biological approach mean?
A perspective that emphasises the importance of physical processes in the body such as genetic inheritance and neutral function.
What does genetic explanations means?
Genes make up chromosomes and consist of DNA which codes the physical features of an organism (eye colour, height) and psychological features (mental disorder, intelligence). Genes are transmitted from parents to offspring (inherited)
What does neural explanations mean?
The view that physical and psychological characteristics are determined by the behaviour of the nervous system in particular the brain as well as the neurons.
What does genetic explanation mean?
Some mental disorders appear to have
a stronger biological component than others, and OCD is a good example of a condition that may be largely understood as biological in nature. One form of biological explanation is the genetic explanation - genes are involved in individual vulnerability to OCD.
What did Lewis do?
Lewis (1936) observed that of his OCD patients 37% had parents with OCD and 21% had siblings with OCD
this suggests that OCD runs in families, although what is probably passed on from one generation to the next is genetic vulnerability not the certainty of OCD.
What does the diathesis stress model say?
That certain genes leave some people more likely to suffer a mental disorder but it is not certain - some environmental stress is necessary to trigger the condition
What is candidate gene?
Researchers have identified genes which create vulnerability for OCD called candidate genes. For example, the gene 5HT1-D beta is implicated in the efficiency of transport of serotonin across synapses
some of these genes involved in regulating the development of the serotonin system.
What does OCD polygenic mean?
OCD seems polygenic. This means that OCD is not caused by one single gene but that several genes are involved. Taylor (2013) has 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 a swell as serotonin both neurotransmitters believed to have a role in regulating mood.
What does different types of OCD mean?
One group of genes may cause OCD in one person but a different group of genes may cause the disorder in another person. The term used to describe this is aetiologically heterogenous meaning that the origin (aetiology) of OCD has different causes (heterogenous). There is also some evidence to suggest that different types of OCD may be the result of particular genetic variations, such as hoarding disorder and religious obsession
Why is good supporting evidence a strength?
There is evidence from a variety of sources for the idea that some people are vulnerable to OCD as a result of their genetic make up. 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. This strongly suggests a genetic influence on OCD.
Why is too many candidate genes a limitation?
Although twin studies strongly suggest that OCD is largely under genetic control, psychologist have been much less successful at pinning down all the genes involved. One reason for this is because it appears that several genes are involved and that each genetic variation only increases the risk of OCD by fraction. The consequence is that a genetic explanation is unlikely to ever be very useful because it provides a little predictive value.
Why environmental risk factors a limitation?
It seems the environmental factors can also trigger or increase The risk of developing OCD (the diathesis stress model). For example Cromer et al (2007) found that over half the OCD patients in their sample had a traumatic events in the past and that OCD was more severe in those with more than 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 on the environmental causes because we are more able to do something about these.
What is neural explanation?
The genes associated with OCD are likely to affect the levels of key neurotransmitter as well as structures the brain.
What is the role of serotonin?
One explanation for OCD concerns the role of the neurotransmitter serotonin, which is believed to help regulate mood. Neurotransmitters are responsible for relaying information from one neuron to another. If a person has low levels of serotonin then normal transmissions of mood relevant information does not take place and mood and sometimes other mental processes are affected. At least some cases of OCD may be explained by a reduction in the functioning of the serotonin system in the brain
What is decision making systems?
Some cases of OCD and in particular hoarding disorder, seem to be associated with impaired decision making. This in turn may be associated with abnormal functioning of the lateral (Side bits) of the frontal lobes of the brain. The frontal lobes are the front part of the brain (behind forehead) that are responsible for logical thinking and making decisions. There is also evidence to suggest that an area called the left parahippocampalgyrus associated with processing unpleasant emotions functions abnormally in OCD.
