Psychopathology: The biological approach to explaining OCD

Question 1

What are the 2 explanations for explaining OCD?

Answer 1

• Genetic explanations
• Neural explanations

Question 2

What is meant by nature vs nurture?

Answer 2

This is a debate between involving whether human behaviour is determined by environment or by a person’s genes (nature)

Question 3

How do family studies (e.g brothers , sisters, or mothers and children) may be useful when investigating the genetic basis of adnormality?

Answer 3

It is useful to study inheritance.

Question 4

What is monozygotic twins?

Answer 4

Identical twins

Question 5

What is dizygotic twins?

Answer 5

Non-identical twins

Question 6

Why are monozygotic and dizygotic twins used to study?

Answer 6

Monozygotic twins are better as they can find a common trait between them.

Question 7

What other reasons , apart from genetics , might explain why members of the same family are more likely to develop OCD?

Answer 7

They are more likely due to stress or parenting styles.

Question 8

What are the genetic explanations for explaining OCD?

Answer 8

Mental disorders are inherited — individuals inherit specific genes from their parents that are related to OCD

Gene = part of the chromosome that carries information in the form of DNA

This explanation includes…
* COMT gene
* SERT gene
* diathesis stress

Question 9

Define a gene.

Answer 9

A part of the chromosome that carries information in the form of DNA.

Question 10

What is the COMT gene?

Answer 10

The COMT gene is a gene that regulates the function of dopamine. It appears that this gene is also mutated in individuals with OCD. However this mutation causes the opposite effect as the SERT mutation discussed above. The mutated variation of the COMT gene found in OCD individuals causes a decrease in the COMT activity and therefore a higher level of dopamine.

Question 11

What is the SERT gene?

Answer 11

The gene which affects the transport of serotonin, causing lower levels of serotonin which is associated with OCD.

Question 12

What is diathesis stress?

Answer 12

The theory is that mental and physical disorders develop from a genetic or biological predisposition for that illness (diathesis) combined with stressful conditions that play a precipitating or facilitating role but are not the sole reason why an individual can develop OCD.

Question 13

What are neutral explanations of explaining OCD?

Answer 13

Genetic factors affect certain brain circuits

this explanation includes…
* abnormal levels of neurotransmitters
* abnormal brain circuits

Question 14

What are abnormal levels of neurotransmitters?

Answer 14

• Dopamine levels are thought to be abnormally high in people with OCD.
• Animal research has found that high doses of drugs enhancing dopamine levels result in stereotypical movements resembling compulsive behaviours found in OCD patients.
• Low levels of serotonin are also associated with OCD.
• Antidepressant drugs that increase serotonin activity have been shown to reduce symptoms of OCD, whereas antidepressants that have less effect on serotonin do not reduce OCD symptoms.

Question 15

Define neurotransmitter.

Answer 15

A chemical substances that transmit nerve impulses across a synapse. e.g dopamine.

Question 16

Define dopamine.

Define serotonin.

Answer 16

A neurotransmitter in the brain that affects motivation and drive. Dopamine levels are thought to be abnormally high in people with OCD.

Serotonin regulates mood and lower levels of serotonin are associated with mood disorders, such as depression.

Question 17

What are concordance rates?

Answer 17

A measure of genetic similarity.

Question 18

Explain what brain scans show: abnormal brain circuits.

Answer 18

The orbital frontal cortex sends a message of panic to the caudate nucleus.

A normal brain would decide whether or not this issue is important and if it is, it would get passed on to the thalamus to take action.

If the message isn’t important or has already been dealt with it will filter out ending the circuit.

However, in a brain of an OCD sufferer, the caudate nucleus does not work correctly and sends the potentially faulty message of panic to the thalamus which then carries out the action e.g. washing hands.

This will keep repeating on a loop which is why someone with OCD performs compulsions which are repetitive rituals.

For example, a non-suffer of OCD may have an impulse to wash dirt from their hands; once this is done the impulse to perform the activity stops and so does the behaviour. It may be that the brains of those with OCD have difficulty switching off these impulses so that they turn into obsessions, resulting in compulsive behaviour.

Question 19

What does the biological approach assume?

Answer 19

Psychological abnormalities are symptoms of underlying physical causes.

Question 20

What are 4 evaluation points for explaining OCD?

Answer 20

+ Research support
+ Research from twin studies
+ Cultural rather than genetics
- Reductionist

Question 21

A03: Reductionist

Answer 21

The biological approach does not take into account cognitions (thinking) and learning. Some psychologists suggest that OCD may be learnt through classical conditioning and maintained through operant conditioning stimulus, for example, dirt is associated with anxiety and this association is then maintained through operant conditioning, where a person avoids dirt and continually washes their hands. This hand washing reduces their anxiety and negatively reinforces their compulsions. Thus, we may need to take an interactionist approach rather than stating OCD originates from one cause.

Question 22

A03: Research from twin studies

Answer 22

Further support for the biological explanation of OCD comes from twin studies which have provided strong evidence for a genetic link. Nestadt et al. (2010) conducted a review of previous twin studies examining OCD. They found that 68% of identical twins and 31% of non-identical twins experience OCD, which suggests a very strong genetic component. The fact that the concordance rate is never 100% means environmental factors must play a role too.

Question 23

A03: Cultural rather than genetics

Answer 23

OCD may be culturally rather than genetically transmitted as the family members may observe and imitate each other’s behaviour, as predicted by social learning theory. Alternatively, family members might be more vulnerable to OCD because of the stressful environment rather than because of genetic factors.

Question 24

A03: Research support

Answer 24

One strength of the biological explanation of OCD comes from research from family studies. Lewis (1936) examined patients with OCD and found that 37% of the patients with OCD had parents with the disorder and 21% had siblings who suffered. Research from family studies, like Lewis, provide support for a genetic explanation to OCD, although it does not rule out other (environmental) factors playing a role.