The biological approach-Explaining OCD

Question 1

A01

Outline Genetic explanations of OCD

genes are involved in individual vulnerability of OCD

Answer 1

• The genetic explanation suggests ppl have genetic vulnerability towards developing OCD
  Family studies
  For e.g Lewis et al. found that of his OCD patients
  37% had parents with OCD
  21% siblings with OCD, suggests OCD runs in family
  OCD IS POLYGENIC
• OCD is polygenic, meaning OCD is not caused by single gene but combination of gene variations Taylor-found up to 230 different genes are involved in its development
  DIFFERENT TYPES OF OCD .
  one group of genes may cause OCD in one person but a different group of genes may cause the disorder in another person
  OCD is aetiologically heterogeneous -means origins of OCD vary from person to person , & diff types of OCD may be result of particular gene variations
  *CANDIDATE GENES
• Researchers identified candidate genes as genes that create vulnerability to OCD
  two examples of genes linked to OCD:
• COMT gene- variation of this gene results in high levels of dopamine-common in patients with OCD
• SERT gene-Affects transport of neurotransmitters
  low levels of serotonin to be active in brain-associated with OCD**

Question 2

A01

The role of neurotransmitters in OCD

Biological explanations of OCD: Neural explanations

Answer 2

Both neurotransmitters serotonin & dopamine play a role in OCD
* Serotonin regulates mood & low levels of serotonin are associated with -OCD
* Dopamine-High levels** of dopamine have been associated with symptoms of OCD- like compulsive behaviours

Question 3

A01

The role & structure of the brain

Answer 3

specific regions of the brain are involved in OCD
* orbital frontal cortex (OFC) sends signals to thalamus about things that are worrying & converts these emotions into actions
this area of brain is overactive in people who suffer from OCD
The thalamus- instructs person to do certain activity in OCD sufferers
Role & decision making
* Some cases of OCD , like hoarding disorder is associated with impaired decision making , which may be associated with abnormal functioning in the lateral of the frontal lobes ( part of brain responsible for logical thinking & making decisions)

Question 4

A03

Research support from twin studies -genetic explanations-Marini et al

Strength

Answer 4

evidence that ppl are vulnerable to OCD is a result of genetic make up
* Marini et al research on family studies found that person with family member diagnosed with OCD 4 times likely to develop it as someone without
These research studies suggest genetic play important role in development of OCD

Question 5

A03

Genetic explanations of OCD ignores Enviromental risk factors

Limitation

Answer 5

genetic model of OCD ignores enviromental risk factors
>OCD is not entirely genetic
> as enviromental risk factors can trigger development of OCD
> e.g twin studies show greater genetic link to ocd, but twins also share same enviroment , which could trigger OCD
> suggests ocd not entirely genetic in origin

Question 6

A03

Research support-OCD symptoms form conditions biological in origin

Strength

Answer 6

> OCD symptoms form part of conditions known to be biological in origin such as parkinsons disease , which cause muscle tremors & paralysis (Nestadt et al)
if biological disorders produce OCD symptoms , then we assume biological processes underlie OCD suggests biological factors may be responsible for OCD

Question 7

A03

Limitation of neural explanation is that serotonin -serotnonin OCD link is not unique

Limitation

Answer 7

Serotonin-OCD link is not unique to OCD
>Many ppl with OCD experience clinical depression (having 2 disorder together(co-morbidity)
>this depression disrupts action of serotonin
>it could just mean that serotonin levels are low in ppl with OCD because they are depressed
>means serotonin may not be relevant to OCD symptoms