Explanations of OCD

Question 1

two possible explanations of OCD

Answer 1

-OCD is caused by genetics
-OCD is caused by neural abnormalities

Question 2

Genetic explanations (evidence)

Answer 2

-Lewis observed that of his OCD patients, 37% had parents with OCD and 21% had sibling with OCD

Question 3

what is a model they used to describe genes and describe it

Answer 3

-Diathesis- stress model
-certain genes make some more likely to develop a mental disorder but it is not certain
-shows that there needs to be some environmental stress to trigger

Question 4

example of OCD in diathesis model

Answer 4

if someone suffers from OCD, it doesn’t definitely mean their child will suffer it just means they are more vulnerable to it being triggered

Question 5

what does polygenic mean

Answer 5

-that OCD is not caused by one single gene but by a combination of genetic variations that together significantly increase vulnerability

Question 6

example of OCD as polygenic

Answer 6

-Taylor analysed previous studies and found evidence that up to 230 different genes may be involved in OCD

Question 7

example of polygenic genes involved in triggering OCD

Answer 7

-SERT (transport of seratonin creating lower level of this neurotransmitter)
-COMT (regulates dopamine, higher levels of dopamine more common in patients w OCD than w/out, lower activity of COMT gene= higher dopamine)

Question 8

different types of OCD

Answer 8

-OCD is aetiologically heterogenous (the origins of OCD vary from one person to another/ groups of genes can be diff and still have OCD)

Question 9

neural explanations for OCD

Answer 9

-the levels of key neurotransmitters
-the structure of the brain

Question 10

two neural explanations

Answer 10

-the role of serotonin
-decision-making systems

Question 11

the role of serotonin

Answer 11

-involvement of neurotransmitters
-if person has low levels of serotonin, normal transmission of mood-relevant info does not happen and may experience low moods
-higher levels of dopamine may be associated with OCD

Question 12

Decision-making systems

Answer 12

-influences by abnormal brain circuits (between OFC and basal ganglia)
-relatively high level of activity in the OFC(orbitofrontal cortex), part of brain responsible for logical thinking linked to OCD

Question 13

example of OCF function

Answer 13

impulse control
-non-sufferer may have an impulse to wash dirt from their hands, once this is done the behaviour stops
-OCD sufferer: have difficulty switching off impulses so they turn into obsessions resulting in impulsive behaviours

Question 14

converting sensory info into thoughts

Answer 14

-if brain receives an impulse, the OCF would initiate an activity and then stops the activity when the impulse lessens

Question 15

part of the brain linked to OCD

Answer 15

-Para hippocampal gyrus linked to processing unpleasant emotions (e.g. disguist), if brain cant process emotion properly may lead to OCD
-Basal ganglia (cluster of neurones at base of forebrain involved in multiple processes)

Question 16

example of an abnormal brain circuit

Answer 16

-the basal ganglia normally suppresses signals from the OFC
-the OFC signals thalamus about things to worry abt such as germs
-when basal ganglia is damaged, it fails to supress worry signals and thalamus is alerted which send signals back to OCF acting as worry circuit

Question 17

what supports the neural explanations

Answer 17

-PET scans taken while OCD is active
-shows a heightened activity in the OFC