Biological approach to explaining OCD

Question 1

What is the definition of genetic explanations?

Answer 1

• genes make up chromosomes and consists of DNA which codes the physical features of an organism and psychological features
• genes are transmitted from parents to offspring

Question 2

What is the definition of neural explanations?

Answer 2

-the view that physical and psychological characteristics are determined by the behaviour of the nervous system particularly the brain and individual neurones

Question 3

Why is OCD thought to be biologically caused?

Answer 3

Individual genes cause vulnerability to OCD
Lewis 1936 - of his OCD patients 37% had parents with it and 21% had siblings with it
Suggests the vulnerability to it runs in families

Question 3

What is the distressing stress model & how is it relevant?

Answer 3

The model that says ppl have a vulnerability to something but need environmental stress to cause it - true of OCD

Question 4

What are candidate genes?

Answer 4

Genes identified as causing OCD - some of these are involved in regulating the development of Serotonin system

Question 5

Why is OCD said to be polygenic?

Answer 5

Polygenic - caused by many genes

Taylor 2013 - 230 genes involved

Question 6

Why is OCD considered aetiologically heterogenous?

Answer 6

One group of genes may cause OCD in one person and a different set of genes will in another person - the origin of OCD has different causes.

Question 7

What are the evaluation points for genetic explanations of OCD?

Answer 7

+ good supporting evidence - twin studies - Nestadt et al. 2010

• too many candidate genes - no genes are really pinned down as causes
• environmental risk factors are not mentioned but are significant - diathesis stress model - OCD not entirely genetic

Question 8

What is the role of serotonin in causing OCD?

Answer 8

Helps regulate mood - insufficient serotonin - normal transmission of mood-relevant information does not occur - mental processes effected

Question 9

How do decision making systems cause OCD?

Answer 9

Abnormal functioning in the frontal lobes of the brain is associated with impaired decision making - hoarding
The parahippocampal gyrus is associated with unpleasant emotions

Question 10

What are the evaluation points for the neural explanation of OCD?

Answer 10

+ some supporting evidence -

• lack of clarity over the exact mechanisms involved - many different brain systems associated with OCD but there isn’t one constant one
• can’t assume neural mechanisms cause OCD - there is a correlation not causation