Lesson 12 The biological approach to understanding OCD- genetic and neural explanations

Question 1

The COMT gene AO1

Answer 1

• COMT gene causes OCD and it regulates the production of the neurotransmitter dopamine where high levels are associated with OCD
• COMT gene has been found to be more common in OCD patients

Question 2

The SERT gene AO1

Answer 2

• affects the transportation of serotonin which results in low levels of serotonin leading to low mood and depressive symptoms
• research by Ozaki (2003) found evidence that 6/7 family members who had OCD had a mutation of the SERT gene
• therefore it seems that OCD does have a genetic bases

Question 3

Positives of genetic explanations

Answer 3

• Nestadt (2000) found that people who had a first degree relative with OCD were 5x more likely to also get the illness supporting the idea that OCD is transmitted genetically
• Billet (1998) found from a meta analysis of 14 twin studies that OCD is 2x more likely to be concordant in identical monozygotic twins rather than dizygotic non identical twins which supports the idea that OCD is transmitted genetically

Question 4

Negatives of genetic explanations

Answer 4

• The concordance rate of OCD is not 100% so therefore OCD cannot be entirely caused by genetic factors and the genetics explanation fails to take into account psychological and environmental factors that might contribute to the cause of OCD
• Contradicted by the behavioural explanation- two process model would suggest OCD is learnt by classical conditioning, then rewarded through reinforcement (operant conditioning). Behavioural approach is widely supported especially since OCD is often treated using behavioural therapies such as exposure which is similar to SD.
• Diathesis stress model would argue OCD is caused by a combination of genes and a trigger in the environment, opposing the genetics argument.

Question 5

Dopamine: Neural Explanations AO1

Answer 5

• A neurotransmitter that affects mood and might be a cause of OCD
• The frontal lobes in the brain have been linked to dopamine activity
• OCD sufferers have high levels of dopamine
• Research on animals have found that high doses of drugs that enhance dopamine levels can induce movements that resemble repetitive and compulsive behaviour, which is similar to what OCD sufferers would experience
• High dopamine levels have also been linked to over activity in the basal ganglia area in the brain

Question 6

Serotonin: Neural Explanations AO1

Answer 6

• Serotonin is a neurotransmitter that affects mood and might be a cause of OCD
• The frontal lobes have been linked to serotonin activity
• OCD sufferers tend to have low levels serotonin and this can cause depressive symptoms
• Plays a key role in operating the caudate nucleus in the brain, and it seems that low levels of serotonin cause the caudate nucleus to malfunction

Question 7

Positives of the neural explanation

Answer 7

• There has been lots of research to support that neurotransmitters do cause OCD. Anti depressant drugs will increase serotonin levels in OCD patients, and this had led to a reduction of OCD symptoms. Therefore there is good evidence to suggest that low levels of serotonin could be a cause of OCD.
• Ciccerone (2000) supports. He found that giving OCD patients low doses of the drug Risperidone helped to lower dopamine levels and alleviate some of the symptoms. Therefore it seems that high levels of dopamine could be a biological cause for OCD.

Question 8

Negatives of neural explanations

Answer 8

• Neurotransmitters such as dopamine and serotonin might not necessarily cause OCD. Instead low levels of serotonin and high levels of dopamine might be the effect of OCD. Cause and effects must be cautiously examined.
• OCD is co morbid with depression and therefore it is not clear whether low levels of serotonin cause depression or OCD or both. Therefore the link between low levels of serotonin causing OCD is not very clear and needs to be investigated further.