Biological Approach To Explaining OCD

Question 1

Outline the two biological explanations for OCD

Answer 1

1. Genetic explanations- the extent to which OCD is inherited and passed down from parents in our genes
2. Neural explanations- the extent to which levels of neurotransmitters in the brain or malfunctioning of brain structures can have on OCD

Question 2

What are candidate genes

Answer 2

Genes which create vulnerability for a specific disorder

Question 3

What are the two candidate genes for OCD

Answer 3

1. Allele of the COMT gene
2. SERT gene

Question 4

How does an allele of a COMPT gene lead to an increase in dopamine

Answer 4

• the allele produces less COMT, which regulates dopamine
• this variation decreases the amount of COMT in the body which then results in increased levels of dopamine (associated with compulsive behaviour) as it is not regulated

Question 5

How is the SERT gene implicated in OCD

Answer 5

SERT gene affects the transport of seritonin, causing a decrease in seritonin levels

Question 6

What are two neural explanations for OCD

Answer 6

1. Influence of neurotransmitters
2. Abnormal brain circuits- the ‘worry circuit’

Question 7

Outline two neural transmitters that have been implicated in OCD

Answer 7

1. Dopamine- levels are too high in people with OCD
2. Seritonin- levels are too low in people with OCD

Question 8

Outline how seritonin is implicated in OCD

Answer 8

Decreased levels lead to obsessive thoughts and anxiety

Question 9

Outline how dopamine is implicated in OCD

Answer 9

Increased/excessive levels lead to compulsive behaviour

Question 10

What is the worry circuit

Answer 10

• orbifrontal cortex (OFC) sends ‘worry signals’ to the thalamus
• these are normally suppressed by the caudate nucleus
• people with OCD tend to have a damaged caudate nucleus, which results in the thalamus being altered and confirming the ‘worry’ to the OFC