4.1.4 BIOLOGICAL APPROACH TO EXPLAINING OCD

Question 1

what is the biological explanation of OCD?

Answer 1

• the biological approach is known as the medical model as it explains all behaviour through our biology
• sees OCD and other abnormalities in the same way as it sees physical illness, explaining it by abnormal biological processes

Question 2

what are the genetic explanations?

Answer 2

these are hereditary influences transmitted from parent to offspring by genetic transmission

Question 3

OCD seems to be polygenic what does this mean?

Answer 3

OCD isn’t caused by one single gene but by a combination of genetic variations that together cause significantly increased vulnerability

Question 4

what are candidate genes?

Answer 4

researchers have identified candidate genes as genes that create vulnerability to OCD

• can be found in gene mapping studies where genetic material is compared from OCD sufferers with non-sufferers

Question 5

there are different types of genes that cause OCD
explain this

Answer 5

one gene variation or group of genes may cause it in one person, but another sufferer of OCD could have a different variation of genes

Question 6

what did Taylor (2013) find?

Answer 6

found evidence from previous studies that there are up to 230 different genes which may be involved in OCD

Question 7

what neurotransmitters are believed to have a role in regulating mood?

Answer 7

genes studied in relation to OCD include those involved in the action of dopamine and serotonin

Question 8

what does Tukel et al. (2013) suggest?

Answer 8

• that a variation of the COMT gene may contribute to OCD as it’s more common in patients who suffer from OCD than in those that don’t
• this variation produces higher levels of dopamine and lower activity of the COMT gene

Question 9

how has the 5-HTT gene been linked with OCD?

Answer 9

it affects the levels of serotonin, making them less and these lower levels of the neurotransmitter are linked with OCD

Question 10

what are some strengths of the genetic explanations?

Answer 10

1) a strong evidence base of research, especially within twin studies

2) Nestadt et al. (2010) reviewed evidence that 68% of identical twins will both have OCD compared to 31% of non-identical twins
- Marini et al (2012) found a person with a family member diagnosed with OCD is around 4x as likely to develop it as someone without
- this is a significant link to show that genetics play an important role in the development of OCD
- and that nature (in the nature/nurture debate) is shown to play a large role

3) Grootheest et al. (2005)
- found their genetic link was stronger in children that were sufferers of OCD

Question 11

what are some limitations of the genetic explanations?

Answer 11

1) ignores environmental factors
- twin studies are used as there’s a greater genetic link
- these twins are share the same environment which could also trigger OCD

2) evidence to suggest that identical twins are treated ‘more similar’ in terms of their environment
- eg) expectations, style of dress, extracurricular activities
- than non-identical twins who are treated more as individuals

3) Pato et al. (2001)
- notes that although there seems to be a genetic link between OCD sufferers
- there’s not enough understanding about the actual genetic mechanisms causing OCD

4) Grootheest et al.
- found that the genetic link was stronger in kids that had OCD
- than when the OCD originated in adulthood
- showing the probability of different causes

Question 12

how can OCD be explained through neural explanations?

Answer 12

• can be explained through neural connections and the imbalance / damage these can have
• the neural damage may have been caused by illnesses that affect the immune system, such as different bacteria’s
• the explanation links to the genetic difference that has been found in OCD sufferers
• where the gene influences the levels of key neurotransmitters and the structure in the brain

Question 13

what role does serotonin play?

Answer 13

• a role in regulating mood
• if a person has low levels of serotonin the person can have low moods and other mental processes are often affected
• the reduction of serotonin can explain some cases of OCD

Question 14

what are dopamine levels like in ppl with OCD?

Answer 14

thought to be abnormally high in ppl who suffer from OCD

Question 15

what is the orbital Frontal Cortex (OFC) and what’s it like in ppl with OCD?

Answer 15

• sends signals to the thalamus about things that are worrying you
• is overactive in ppl who suffer from OCD

Question 16

what is the thalamus and what’s it like in ppl with OCD?

Answer 16

• instructs the person to do a certain activity or behaviour
• this could be the OCD behaviour in ppl with OCD

Question 17

what is the the caudate nucleus and what’s it like in ppl with OCD?

Answer 17

• in non-OCD sufferers it surprises the messages from the OFC, and normalises the worry
• in ppl with OCD, it doesn’t complete this job and allows the OFC to make the suffer worry
• can be due to damage / overstimulation

Question 18

some forms of OCD have been linked with poor decision making
what could this be down to?

Answer 18

abnormal functioning in the arterial parts of the frontal lobes
(the parts of the brain responsible for logical thinking and making decisions)

Question 19

what is a strength of the neural connections explanation?

Answer 19

• antidepressants like SSRIs (used to control levels of serotonin) are seen to be effective in reducing OCD symptoms
• which would support the idea of an imbalanced neural network

Question 20

what are three limitations of the neural connections explanation?

Answer 20

1) there’s evidence that environmental triggers can play a large role in triggering OCD
- one study found over 50% of the ppts had suffered a traumatic event which led to their OCD

2) not all OCD sufferers respond positively to antidepressants (serotonin levellers)
- which would show it’s not the neural network causing OCD in those patients

3) biological explanations are reductionist, ignoring the holistic approach