OCD explanations

Question 1

What are the 2 biological explanations for OCD

Answer 1

Genetic and Neural

Question 2

What is meant by genetic vulnerability

Answer 2

Some people appear to be predisposed to develop OCD as a result of their genetic make-up

Question 3

What is meant by OCD being polygenic

Answer 3

230 genetic variations may be involved in OCD

Question 4

What is meant by candidate genes

Answer 4

Specific genes are likely to be involved in vulnerability, e.g. 5HT1-D beta

Question 5

What may different types of OCD be explained by (genetic)

Answer 5

Different genetic bases, e.g. hoarding disorder and religious obsession.

Question 6

Outline genetics explanation - 6 marks (First 3 bullet points)

Answer 6

Researchers have identified specific genes which create a vulnerability for OCD, called candidate genes.

Serotonin genes, e.g. COMT / SERT, are involved in the transmission of serotonin across synapses.

Dopamine genes are also implicated in OCD.

Question 7

Outline genetics explanation - 6 marks (Last 3 bullet points)

Answer 7

Both dopamine and serotonin are neurotransmitters that have a role in regulating mood.

OCD is not caused by one single gene but several genes are involved (polygenic).

Taylor (2013) found evidence that up to 230 different genes may be involved in OCD

Question 8

Evaluate the genetic explanation for OCD based on research evidence (strength)

Answer 8

One strength is evidence for the genetic explanation of OCD

Nestadt et al. (2010) reviewed twin studies and found that 68% of identical twins (MZ) shared OCD as opposed to 31% of non-identical (DZ) twins.

Marini and Stebnicki (2012) found that a person with a family member with OCD is around four times as likely to develop it as someone without.

Therefore, this means that people who are genetically similar are more likely to share OCD, supporting a role for genetic vulnerability.

Question 9

Give a counter evaluation to research evidence supporting the genetic explanation

Answer 9

Thefact that not all twins share OCD tendencies despitehaving the exact same genetics suggest that it cannot be genes alonewhich cause OCD and this biological explanation is biologically reductionist andoversimplified.

This demonstrates environmental stressorsmust play a part in triggering OCD which needs to be considered.

Question 10

Evaluate the genetic explanation based on there being a more complete explanation (weakness)

Answer 10

A diathesis-stress model may be better suited to explaining OCD as it factors in both genetics and psychological factors such as environmental stressors.

This suggests some people may have a genetic vulnerability to develop OCD and providing the right environmental triggers causes its onset.

This would be a more holistic explanation.

Question 11

What is the neural explanation

Answer 11

Abnormal functioning of neurotransmitters and / or brain structures causes OCD

Question 12

What role does serotonin have in OCD (neural)

Answer 12

Abnormal transmission of mood-relevant information contributes to OCD

Question 13

What does the neural explanation believe about dopamine

Answer 13

High levels of dopamine causing OCD is one explanation.

A study by Szechtman et al 1998 found that when animals were given drugs that increased dopamine levels, their behaviours resembled that of obsessive behaviours found in people with OCD.

Question 14

What does the neural explanation believe about serotonin

Answer 14

Low levels of serotonin in patients has been linked with OCD.

Pigott et al (1990) foundanti-depressantdrugs whichincrease serotonin activity have been found to reduce obsessive tendencies andsymptoms in patients.

PET scans on the brain have also found lowlevels of serotonin in sufferers

Question 15

How does the orbital frontal cortex (OFC) affect OCD

Answer 15

Becomes overreactive even when nothing is wrong. Usually just detects when something is wrong / needs attention.

Question 16

How does the basal ganglia system affect OCD

Answer 16

Usually filters out unnecessary thoughts/actions. In OCD, it fails to filter them out.

Question 17

How does the parahippocampal gyrus affect OCD

Answer 17

Usually regulates unpleasant emotions e.g. anxiety. In OCD, becomes overreactive, increasing emotional responses.