7. Biological Explanation for OCD

Question 1

Effect of genetics on causing OCD

Answer 1

• Biological approach offers useful suggestions as to how OCD is caused
• It has been proposed that there is a genetic component to OCD which predisposes some individuals to the illness
• The genetic explanation suggests that whether a person develops OCD is at least partly due to their genes. This may explain why patients often have other family members w OCD

Question 2

What did Billet et al (1998) & Bellodi et al (2001) claim

Answer 2

That genetic factors play a role in the development of OCD: Using evidence from twin studies & family studies, they showed that close relatives are more likely to have the disorder than more distant relatives

Question 3

What did Mckeon & Murray (1987) claim

Answer 3

Patients w OCD are more likely to have first degree relatives who suffer from anxiety disorders

Question 4

What did Lewis (1936) & Pauls et al (2005) claim

Answer 4

There is a higher percentage of OCD sufferers in relatives of patients w OCD than in the control group without OCD

Question 5

Issue with these claims

Answer 5

Outdated - very old research

Question 6

Genetic explanations: What are candidate genes

Answer 6

Genes which, through research, have been implicated in the development of OCD

Question 7

What is a possible candidate gene

Answer 7

The SERT gene - involved in regulating serotonin, a neurotransmitter which facilitates message trasnfer across synapses (5HT1-D beta)

Question 8

What is another possible candidate gene

Answer 8

The COMT gene - this regulates the production of dopamine
Dopamine effects motivation & drive

Question 9

Genetic explanations: The diathesis-stress model

Answer 9

Suggests that ppl gain a vulnerability towards OCD through genes but an environmental stressor is also required. This could be a stressful event, eg a bereavement

Question 10

Genetic explanations: Polygenic

Answer 10

OCD is thought to be polygenic - this means that its development is not determined by a single gene but a few (maybe as many as 230 genes) - this means that there is little predictive power from this explanation

Question 11

Aetiologically heterogeneous

Answer 11

The idea that:
- the origin of OCD has different causes
- different genetic variation or genes cause the disorders in different ppl

Question 12

Evaluations of genetic explanations: GOOD

Answer 12

• There is some evidence to suggest there is a genetic component to the disorder. One of the best sources of evidence for the importance of genes is twin studies (Nestadt, 2010)

Question 13

Evaluations of genetic explanations: BAD

Answer 13

• Family studies could also be used to explain environmental influences
• Close relatives of OCD sufferers may have observed & imitated the behaviour (SLT)
• It is difficult to untangle the effects of environment & genetic factors

Question 14

Candidate genes CONS

Answer 14

• There are too many genes involved
• Psychologists have not been successful at pinning down all the genes involved
• Each genetic variation only increases the risk of OCD by a fraction

Question 15

What do neural explanations entail

Answer 15

• The genes associated with OCD are likely to affect the levels of key neurotransmitters as well as structures of the brain
• These are neural explanations

Question 16

Neural explanations: Basal ganglia

Answer 16

Researchers has implicated a part of the brain known as the basal ganglia
- This area of the brain is responsible for innate psychomotor functions

Question 17

What did Rapoport & Wise (2010) propose

Answer 17

• Proposed the hypersensitivity of the basal ganglia gives a rise to the repetitive motor behaviours seen in OCD, for eg, repetitive washing/cleaning/checking
• Link with striatum function

Question 18

Neural explanations: Orbitofrontal cortex (OFC)

Answer 18

• Other brain areas believed to be involved in OCD. Include the orbitofrontal cortex (OFC) & the thalamus
• OFC involved in decision making behaviours
• Thalamus - function is cleaning, checking & other safety behaviours

Question 19

Neural explanations: Frontal lobe

Answer 19

Involved in decision making & worry about social behaviours

Question 20

What would an overactive thalamus result in

Answer 20

• An increased motivation to clean or check for safety.
• If the thalamus was overactive, the OFC would also become overactive as a result

Question 21

What would an overactive OFC reuslt in

Answer 21

• Increases anxiety & increased planning to avoid anxiety

Question 22

What do lower levels of serotonin cause

Answer 22

• Low levels of serotonin causes normal transmission of mood-relevant info to take place.
• Lower levels can lead to depression & mood instability
• This affects mood & other mental processes

Question 23

The role of neurotransmitters: PROS

Answer 23

• Allows medication to be developed which helps sufferers

Question 24

The role of neurotransmitters: CONS

Answer 24

• Drugs are not completely effective
• Just bc administering SSRIs increase OCD symptoms, does not mean that lower levels of serotonin are a cause of the OCD
• There is time delay between taking drugs to target the condition & any improvements being made & yet the chemical imbalance is addressed in hours

Question 25

Areas of the brain: PROS

Answer 25

• Advances in technology have allowed researchers to investigate specific areas of the brain more accurately, & OCD sufferers do seem to have excessive activity in the orbital frontal cortex
• Cleaning & checking behaviours are ‘hard-wired’ in the thalamus

Question 26

Areas of the brain: CONS

Answer 26

• The repetitive