Biological approach to explaining OCD

Question 1

what are the biological explanations to explaining OCD

Answer 1

• serotonin
• dysfunction of brain areas
• parahippocampal gyrus
• candidate genes

Question 2

what is the neural explanation involving serotonin for OCD

Answer 2

• The neurotransmitter is believed to help regulate mood
• A neurotransmitter is a chemical messenger.
• If serotonin levels are disrupted, that means that messages involving mood are not reaching the right parts of the brain. (re-uptake)
• This could cause a disturbance in cognition, emotions and behaviour (OCD)

Question 3

what is the neural explanation involving the dysfunction of brain areas for OCD

Answer 3

frontal lobe:
- Some types of OCD (hoarding) seem to involve impaired decision making
- Decision making takes place in the frontal lobe (behind your forehead).
- There is research which suggests that the lateral part (sides) of the frontal lobe function abnormally in OCD patients in comparison to controls
- Deficit in blood flow = does not function as accurately - impaired decision making

Question 4

what is the explanation involving the parahippocampal gyrus for OCD

Answer 4

• There is evidence to suggest that the left parahippocampal gyrus, associated with processing unpleasant emotions, functions abnormally in patients with OCD. –> overactive, heightened emotions
• Linked to the serotonin explanation is the possibility that a faulty gene has caused that disruption of serotonin:
  → can increase the likelihood of re - uptake

Question 5

what is the explanation involving candidate genes for OCD

Answer 5

• The SERT gene - 5-HTT - has been identified as a candidate gene for OCD.
• This gene determines how effective the transport of serotonin will be around the brain (across synapses).
• Carrying the SERT gene causes a disruption to serotonin transportation and therefore OCD
• Genes involved in dopamine transportation have also been identified as possible causes –> particularly the COMT gene - (COMT regulates the production of dopamine)

Question 6

what is the -ve point for the biological explanations

Answer 6

Alternative Genes

Question 7

expand on the alternative genes explanation

Answer 7

-Taylor carried out a huge meta-analysis and uncovered over 230 different genes which could be implicated in the development of OCD.

• Furthermore, psychologists believe that different types of OCD (hoarding, religious obsession, germ obsession) could be caused by DIFFERENT genes. → “aetiologically heterogeneous” (origin for OCD has more than one cause)

Question 8

what are the +ve ao3 twin studies for biological approach to explaining OCD

Answer 8

• Twin studies can be used to show that OCD has biological roots because MZ twins share 100% of the same genes and DZ twins only share 50%.
• By comparing concordance rates across both sets of twins we can separate out the effects of nature and nurture.
• If concordance rates are much higher in MZ twins, then this extra “likeness” should be due to genetics, because both MZ and DZ twins share the same environment.
• The higher the concordance rate in MZ compared to DZ twins, the stronger the evidence for Biology.
• There are many twin studies which have found support for the hypothesis that OCD is genetic
• a meta – analysis by Nestadt (2010) found 68% of MZ twins shared OCD compared to 31% DZ twins
• Furthermore, family studies have shown that people with a first degree relative with OCD have a 5 times greater chance of developing it themselves!

Question 9

what are the -ve ao3 family studies for biological approach to explaining OCD

Answer 9

• There are many issues with FAMILY studies- particularly pertinent is that it is very difficult to separate out the effects of nature (biology) and nurture (environment) when people grow up in the same home.
• They could just be copying each other or learning from one another.
• Concordance rates for twin studies are never conclusive- (never 100% vs 0%) so the DIATHESIS STRESS model could be the most VALID explanation.

Question 10

what is the -ve AO3 alternative explanation

Answer 10

• There is an abundance of evidence to suggest that many sufferers of OCD have suffered a traumatic event in their past.
• Therefore some psychologists believe that in fact NURTURE is much more important than NATURE in explaining this disorder

Question 11

what is the +ve ao3 point real life applications

Answer 11

• The fact that anti-depressants can be used to drastically reduce OCD symptoms (i.e. they work!) gives validity to the neural explanation.
• I.e. if drugs which INCREASE the transportation of serotonin cure the symptoms of OCD, then the theory must be valid!
• Hundreds of supporting studies have been published, all lending validity to this theory.