Biological explanations of OCD

Question 1

two explanations

Answer 1

• genetic
• neural

Question 2

genetic explanation

Answer 2

• COMT gene
• SERT gene

Question 3

COMT gene - genetic explanation

Answer 3

• causes OCD = candidate gene
• regulates the production of dopamine = high levels associated w/ OCD
• psychs use family or twin studies
• OCD is classed as polygenic = not one single gene is responsible for disorder
• many genes = candidate genes
• COMT gene found to be more common in OCD patients than people who don’t have the illness
• high levels of dopamine = responsible for drive, motivation etc..

Question 4

SERT gene- genetic explanation

Answer 4

• gene affects the transportation of serotonin
  = results in low levels of serotonin
  = low mood + depressive symptoms
• individuals have the SERT gene on chromosome 17
  = mutation in this gene causes OCD
• research found that 6/7 family members had OCD, had a mutation of SERT gene
• may be link between OCD + depression
  = OCD has a genetic basis

Question 5

ads of genetic explanation

Answer 5

• family
• MZ vs DZ

Question 6

disads of genetic explanation

Answer 6

• complex
• behavioural approach

Question 7

family - ads of genetic explanation

Answer 7

• research support for the genetic explanation for OCD
• found that people who had a first degree relative who already had OCD were 5x more likely to get it
• supports the idea that OCD is transmitted genetically

Question 8

MZ vs DZ - ads of genetic explanation

Answer 8

• research supports the idea that OCD is transmitted genetically
• meta-analysis of 14 twin studies
  = OCD is 2x more likely to be concordant in identical MZ twins than DZ twins
• supports the idea that OCD is transmitted by genetics

Question 9

complex - disads of genetic explanation

Answer 9

• OCD is polygenic
• one single gene isn’t responsible for disorder
• OCD has been genetically linked to other illnesses e.g. Tourettes syndrome + autism
• therefore it seems that the genetic cause for OCD is very complex
• might be related to other illnesses too

Question 10

behavioural approach - disads of genetic explanation

Answer 10

• behavioural approach would contradict the genetic explanation for OCD
• the two process model would suggest that OCD can be learnt via classical conditioning
• then rewarded through reinforcement (operant conditioning)
• the behavioural approach has gained lots of support in explaining the cause of OCD
• especially as OCD is often treated using behavioural therapies e.g. exposure (similar to systematic desensitisation)

Question 11

research on genes + OCD

Answer 11

• meta analysis between 1925-1965
• 10,034 MZ + DZ twins
• found that when children had OCD, 45-65% was influenced by genes (main factor)
• when adults had OCD, 27-47% was influenced by genes (more to do w/ environment, genes not main factor)
  = shows that genetics seem to be a strong cause of OCD in children rather than adults

Question 12

twin studies - disads of research on genes + OCD

Answer 12

• majority of twin studies were not performed in controlled conditions
• data is not very objective or scientific
  = may affect the validity + reliability of the results gained from this research
• this might question the idea that OCD is genetic

Question 13

gene mapping - disad of research on genes + OCD

Answer 13

• research didn’t take into account gene mapping when looking at whether OCD is genetic
• gene mapping would look closely at the DNA of twins that had OCD
• compared this w/ twins that didn’t have OCD
• a comparison needs to be made in order to make the results more valid

Question 14

neural explanations - serotonin

Answer 14

• frontal lobes in the brain are linked to serotonin
  = affects mood
• OCD sufferers have low levels of serotonin in the brain
• serotonin plays a key role in operating the caudate nucleus
• low levels of serotonin cause caudate nucleus to malfunction
• caudate nucleus = vital role in how the brain learns, specifically the storing + processing of memories
• works as a feedback processor = uses info from past experiences to influence future actions + decisions

Question 15

neural explanations - dopamine

Answer 15

• dopamine = neurotransmitter affecting mood, potential cause of OCD
• frontal lobes linked to dopamine activity
  = high levels of dopamine for OCD sufferers
• also been linked to over activity in the basal ganglia area in the brain (motor function + learning)
  = cause compulsive + repetitive behaviour

Question 16

ads of neural explanation

Answer 16

• research support

Question 17

disads of neural explanation

Answer 17

• cause + effect
• co-morbid

Question 18

research support - ads of neural explanation

Answer 18

• there’s been lots of support to state that neurotransmitters do cause OCD
• anti-depressant drugs will increase serotonin levels in OCD patients
  = this had led to a reduction of OCD symptoms
  = therefore food evidence to suggest that low levels of serotonin could be a cause for OCD

Question 19

cause + effect - disads of neural explanation

Answer 19

• neurotransmitters such as dopamine + serotonin might not necessarily cause OCD
• instead low levels of serotonin + high levels of dopamine might be the effect of OCD
• therefore we must be cautious when looking at cause + effect of neurotransmitters

Question 20

co-morbid - disads of neural explanation

Answer 20

• OCD is co-morbid w/ depression
• therefore it is unclear whether low levels fo serotonin cause OCD or depression or both
• link between low levels of serotonin causing OCD
  = not very clear + needs to be investigated further