5- biological explanations for OCD

The biological approach would explain OCD as being the result of what type of factors?

Innate

What are the two broad categories of biological explanations for OCD?

Genetic and neural

What research method has been used to suggest that there could be an underlying predisposition for OCD that is passed on?

Family and twin studies

Rather than OCD certainly being passed on, what is it that is most likely inherited?

Genetic vulnerability

What theory refers to a genetic predisposition that requires an environmental trigger?

Diathesis-stress model

What type of genes have been linked to OCD by creating a vulnerability for the disorder?

Candidate genes

What term is used to refer to the fact that there are multiple genes linked to OCD?

Polygenic

Up to how many genes have actually been found to be involved in OCD?

230

Which gene is linked to the efficiency of transport of serotonin (and can cause low levels of serotonin)?

SERT

Which gene is associated with the regulation of dopamine?

COMT

Different groups of genes may cause OCD in one person, but a different group may cause the disorder in another person. What is the name for this?

Aetiologically heterogeneous

Give two different forms of OCD that may suggest that different types of OCD may be the result of particular genetic variations.

Hoarding or religious disorders.

What are two examples of neural explanations for OCD?

Brain structure and biochemical factors

Which part of the brain is over-active in OCD patients, the function of which is decision making so when overactive, it leads to increased anxiety and the need to organise/plan behaviour?

OFC

What do the letters OFC stand for?

Orbito-frontal cortex

Which part of the brain has been found to be larger in OCD patients, the function of which includes cleaning, checking and other safety behaviours?

Thalamus

Which area of the brain has been linked to OCD when it malfunctions and is associated with processing unpleasant emotions?

Parahippocampal gyrus

According to the biochemical explanation, OCD may result from low levels of which neurotransmitter or a malfunction of receptors for this neurotransmitter?

Serotonin

What percentage of people have OCD?

2%

What percentage of people with OCD did Pauls find had a relative with OCD?

10%

What is the concordance rate for OCD in MZ twins and DZ twins, suggesting a genetic contribution?

66% (MZ), 31% (DZ)

Who completed this research?

Nestadt

What technique has been used to show that brain structures differ in OCD patients from a control group, thereby supporting a neural explanation?

Brain scans

What is provided to OCD patients which helps reduce their symptoms, suggesting a biochemical component to the disorder?

SSRIs

What type of determinism does this approach to explaining OCD suffer from?

Biological

What could be an alternative explanation for why people in the same family develop OCD?

Shared environments

Who found that an environmental trigger was important for the development of OCD, suggesting a more interactionist approach between nature and nurture?

Cromer

What fraction of patients in Cromer’s study of OCD patients had a traumatic event in their past?

Half

What happened to OCD when there was more than one trauma for Cromer’s patients?

More severe

What is a problem with neural explanations for OCD?

Data is correlational

What does this mean?

There is no cause and effect, so we are unsure whether increased activity in the OFC or serotonin deficiency causes OCD or is a consequence of it.

What alternative treatment is also effective for OCD which does not target biological factors?

CBT

Which explanation is considered better by considering how OCD relates to stressful events, helping to find a more suitable treatment?

Diathesis-stress model