psychopathology: explanations of OCD Flashcards
what are the 2 explanations of OCD
- GENETIC
- NEURAL
What percentage of patients with OCD observed by Lewis had a parent with OCD?
37%
This statistic indicates a potential genetic link in the occurrence of OCD.
What percentage of patients with OCD observed by Lewis had siblings with OCD?
21%
What does the familial occurrence of OCD suggest about its genetic explanation?
OCD runs in families > This suggests that individuals may inherit specific genes that increase vulnerability to OCD.
Is OCD caused by a single gene or multiple genes?
Multiple genes > OCD is considered polygenic
How many different genes did Taylor find evidence may be involved in OCD?
Up to 230 different genes
which genes are involved in OCD
COMT gene
SERT gene
one form of the COMT gene has been found to be more common in OCD patients compared to control group
Fill in the blank: OCD is considered _______.
polygenic
AO3: genetic > research to support
There is support for the genetic explanation of OCD
Support comes from twin studies. Nestadl et al reviewed previous twin studies and found that 68% of MZ twins shared OCD as opposed to 31% of non-identical twins.
STRENGTH as this suggests that there is a strong genetic basis for OCD and the closer you are related to the person who has OCD the more likely you are to develop it.
COUNTER: Twin studies make the assumption that MZ are more similar than DZ only in terms of genes. But MZ may also be more similar in terms of shared environment. This suggests that we cannot conclude that the OCD is due to shared genes, environmental factor may play more of a role.
So we** cannot establish a cause and effect relationship.**
AO3: genetic > 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 their past and that is was more severe in those that had a traumatic event.
WEAKNESS as this suggests that OCD cannot be entirely genetic in origin. There is a much greater risk of developing OCD if we have both genetic vulnerability and then an environmental trigger (diathesis- stress model). As a result, the genetic explanation only provides a partial explanation for OCD.
state the 3 neural explanations
- neurotransmitters
- abnormal brain structures
- abnormal brain circuits
What neurochemicals are associated with OCD?
Abnormal levels of serotonin and dopamine.
These neurotransmitters are linked to mood-related information and obsessive thoughts.
What effect do high doses of drugs that enhance dopamine levels have on behavior?
Induce stereotyped movements in animals resembling compulsive behaviors in OCD patients > This finding is based on animal studies (Szechtman et al).
this suggest dopamine levels are high in those with OCD
What is the relationship between serotonin levels and mood in OCD patients?
Low serotonin levels can prevent normal transmission of mood-relevant information, leading to low moods.
Which brain structure is associated with impaired decision making in OCD?
(abnormal brain structures)
Lateral frontal lobes > This area is responsible for logical thinking and decision making.
What brain area functions abnormally in OCD patients?
(abnormal brain structures)
Left parahippocampal gyrus > this is associated with processing unpleasant emotions,
What is the role of the caudate nucleus in the brain’s worry circuit?
(abnormal brain circuits)
It normally suppresses signals from the orbitofrontal cortex (OFC). > In turn, the OFC sends signals to the thalamus about things that are worrying such as a potential germ hazard.
What happens when the caudate nucleus is damaged in someone with OCD?
(abnormal brain circuits)
It fails to suppress minor ‘worry’ signals, alerting the thalamus > this sends signals back to the OFC creating a ‘worry’ circuit.
What does PET scan activity indicate in OCD patients with germ obsessions?
(abnormal brain circuits)
Heightened activity in the orbitofrontal cortex (OFC) when holding a dirty cloth.
Fill in the blank: Low levels of _______ are associated with OCD.
serotonin
True or False: High levels of dopamine are linked to normal behavior in OCD patients.
False
Fill in the blank: The caudate nucleus is involved in suppressing signals from the _______.
orbitofrontal cortex
What condition is specifically mentioned as being associated with impaired decision making in OCD?
Hoarding disorder
AO3: neural explanation > real life application
There is a real-life application from the neural explanation
Some antidepressants work purely on the serotonin system, increasing levels of this neurotransmitter. Such drugs are effective in reducing OCD symptoms.
STRENGTH as this supports the neural explanation as it suggests that abnormal levels of serotonin is involved with OCD symptoms.
COUNTER: However, many people with OCD experience depression. This suggests that depression probably involves disruption to the
action of serotonin. This suggests that when it comes to serotonin as a possible basis for OCD, it could simply be that serotonin activity is disrupted in many people with OCD because they are depressed as well. Therefore suggesting serotonin may not explain the OCD at all.
