The biological approach to: explaining OCD Flashcards
The genes associated with OCD are likely to affect the levels of key _________________ as well as…
neurotransmitters, structures of the brain
What is serotonin believed to help regulate?
Mood
What are neurotransmitters responsible for?
Relaying information from one neuron to another
What happens in the brain if a person has low levels of serotonin?
Normal transmission of mood-relevant information doesn’t take place
What may a person experience as a result of low levels of serotonin
Low moods and other mental processes being affected
True/False: At least some cases of OCD may be explained by a reduction in the functioning of the serotonin system in the brain
True
True/False: Some cases of OCD seem to be associated with impaired decision-making
True
Which disorder in particular related to OCD seems to be associated with impaired decision-making?
Hoarding disorder
Some cases of OCD seem to be associated with impaired decision-making. Which part of the brain may this in turn be associated with?
Abnormal functioning of the lateral (side bits) of the frontal lobes of the brain
Frontal lobes
Frontal part of the brain that are responsible for logical thinking and making decisions, located behind your forehead
There is also evidence to suggest than an area called what functions abnormally in OCD?
The parahippocampal gyrus
What is the parahippocampal gyrus associated with?
Unpleasant emotions
Give an example of supporting evidence for neural explanations of schizophrenia
Any from antidepressants that work purely on serotonin are effective in reducing OCD symptoms and OCD symptoms form part of conditions that are known to be biological in origin (Parkinson’s disease)
Antidepressants that work purely on serotonin are effective in reducing OCD symptoms. How does this support neural explanations?
Suggests that serotonin may be involved in OCD
What’s the main argument against the involvement of serotonin in OCD
The serotonin-OCD link may not be unique to OCD - many people with OCD also experience clinical depression (co-morbidity)
Co-morbidity
Having two disorders together
Many people with OCD also experience clinical what?
Depression
What’s the problem with many people with OCD also experiencing clinical depression when it comes to evaluating the effectiveness of antidepressants for OCD?
This depression probably involves disruption to the action of serotonin - it could simply be that serotonin activity is disrupted in many people with OCD
Depression involving disruption to the action of serotonin leaves us with a logical problem when it comes to…
serotonin as a possible basis for OCD
True/False: OCD symptoms form part of conditions that are known to be biological in origin
True
Give an example of a condition that’s known to be biological in origin which’s symptoms include symptoms of OCD
Parkinson’s disease
If a biological disorder produces OCD symptoms then we may assume…
the biological processes underlie OCD
The fact that a biological disorder such as Parkinson’s disease produces OCD symptoms suggests…
that biological factors may be responsible for OCD (e.g. serotonin and the processes underlying certain disorders)
There is evidence to show that some ______ systems do not work normally in people with OCD
neural
According to the biological model of mental disorder the fact that some neural systems don’t work normally in people with OCD is most easily explained by…
brain dysfunction causing the OCD
What’s the problem with saying that brain dysfunction causes OCD?
There is simply a correlation between neural abnormality and OCD - such correlations don’t necessarily indicate a causal relationship
True/False: It is quite possible that OCD (or its accompanying depression) causes abnormal brain function
True
True/False: OCD is a good example of a condition that may be largely understood as biological in nature
True
What did Lewis find about the involvement of genes in OCD?
When observing patients with OCD 37% had parents with OCD and 21% had siblings with OCD
Lewis observed patients with which condition?
OCD
Lewis observed that __% of his OCD patients had parents with OCD
37%
Lewis observed that __% of his OCD patients had siblings with OCD
21%
What do Lewis’ findings suggest about OCD?
It runs in families
What do Lewis’ findings suggest about what gets passed on from one generation to the next in regards to OCD?
Genetic vulnerability - not certainty of OCD
According to the diathesis-stress model certain genes leave some people more…
likely to develop a mental disorder
The diathesis-stress model says certain genes leave some people more likely to develop a mental disorder, however some…
environmental stress is necessary to trigger the condition (experience)
True/False: Researchers have not yet identified specific genes that create vulnerability for OCD
False, they have
What are candidate genes for OCD often involved in?
Regulating the development of the serotonin system
____-_ beta is implicated in the transport of serotonin across synapses
5GT1-D
True/False: OCD is polygenic
True
Polygenic
Not caused by on single gene but instead a combination of genetic variations that together significantly increase vulnerability
What did Taylor find in their analysis of previous studies into OCD?
Evidence that up to 230 different genes may be involved in OCD
Taylor found evidence that up to how many different genes may be involved in OCD?
230
Genes that have been studied in relation to OCD include those associated with the action of…
dopamine and serotonin
Dopamine and serotonin are both neurotransmitters believed to have a role in doing what?
Regulating mood
True/False: There are different types of OCD
True
True/False: The same group of genes causes OCD in everyone
False, one group of genes may cause OCD in one person but a different group may cause it in another
True/False: OCD is aetiologically heterogeneous
True
OCD is aetiologically heterogeneous. What does this mean?
The origins vary from one person to another
True/False: There is evidence to suggest that different types of OCD may be the result of particular genetic variations
True
Give an example of a source of information that strongly suggests some people are vulnerable to OCD as a result of their genetic make-up
Any from twin studies and family studies
What did Nestadt et al. (2010) find in their review of twin studies?
68% of identical twins shared OCD opposed to 31% of non-identical twins
In Nestadt et al.’s review of twin studies they found that __% of monozygotic twins shared OCD
68
In Nestadt et al.’s review of twin studies they found that __% of dizygotic twins shared OCD
31
What did Marini et al. (2012) find about a person with a family member diagnosed with OCD?
They are around four times as likely to develop it as someone without
One limitation of the genetic model of OCD is that there are also _____________ risk factors
environmental
True/False: OCD appears to be entirely genetic in origin
False, it doesn’t
What did Cromer et al. (2007) find about over half the OCD clients in their sample?
They had experienced a traumatic event in their past
What did Cromer et al. (2007) find about their OCD clients who had experienced one or more traumas?
Their OCD was more severe
What are candidate genes in terms of OCD?
Genetic variations that are possible causes of OCD
What does evidence from animal studies for OCD show?
Particular genes are associated with repetitive behaviours in other species e.g. mice
Although mice and humans share most genes…
the human mind and brain are much more complex. It may not be possible to generalise from animal repetitive behaviour to human OCD
