Biological approach to explaining OCD

Question 1

Neural explanations for OCD (neurotransmitters)

Answer 1

Dopamine levels are high in people with OCD

-Study found that a drug which increased dopamine levels also increased OCD like characteristics

Low levels of serotonin are linked to OCD

-Study found that antidepressants which increased serotonin levels also lowered OCD symptoms

Question 2

Genetic explanations for OCD

Answer 2

COMT gene produces COMT

-which regulates the production of dopamine
-COMT gene in people with OCD is less active, meaning they have more dopamine than regular people

SERT gene lowers serotonin levels

-low levels of serotonin found in people with OCD
-Study found a mutated SERT gene in two families who had OCD

The diathesis stress model proposes that these genes create a vulnerability to OCD, other factors are needed for OCD to develop

Question 3

Neural explanations for OCD (areas of the brain)

Answer 3

Caudate nucleus usually suppresses signals from the Orbifrontal Cortex (OFC)

-OFC sends signals to the Thalamus about worries (e.g germs)

-These worries are not surpressed in people with OCD so are constantly happening

These worries are then sent back to the OFC and remain in a cycle (WORRY CIRCUIT)

This is supported by PET scans taken when symptoms are active

Question 4

AO3 +

Family and twin studies

Answer 4

Nesdadt
-identified 80 people with OCD
- +343 of their 1st degree relatives
-compared them with control group

-he found that people who have a 1st degree relative with OCD are 5x more likely to also have OCD

Twin studies support this - MZ twins are more likely to have OCD if their twin did than DZ twins

Question 5

AO3 +

Real-world application

Answer 5

The mapping of human genomes has led to the idea that certain genes could be linked to particular mental or physical disorders

-Now, if a pregnant mother has the COMT gene, they can have the fertilised egg screened, giving the mother the option to abort

Question 6

AO3 +

Research support for genes from MRI scans

Answer 6

Menzies

-used MRI to produce images of brain activity in:
–OCD patients
–Their families who did not have OCD
–Unrelated people who did not have OCD

It was found that both the OCD patients and their families had less grey matter in their OFC

This supports the idea that biological differences are inherited and could lead to OCD in some people

Question 7

AO3 -

Alternative explanations

Answer 7

Behavioural explanations

-Two process model

-Classical conditioning initiates it :NS (e.g dirt) becomes associated with anxiety

-This is maintained through operant conditioning as by washing hands, the CS (dirt) is avoided

-Obsession is formed, Compulsion of washing hands is formed too