The Biological Approach to explaining OCD

Question 1

What are the three parts to the biological approach?

Answer 1

Genetic explanation and the Neural explanations ( neurochemistry and neuroanatomy)

Question 2

Within the neural explanation what are the two topics?

Answer 2

Neurochemistry and Anatomy

Question 3

What is the genetic explanation regarding the Biological approach to do with inheritance and how is it checked?

Answer 3

OCD is likely to be inherited via parents through genes and DNA. This can be checked by examining if a patient’s family also have OCD. If this is the case, we’d expect first degree relatives to have a high rate of OCD, (parents, brothers/ sisters, children )

Question 4

What did Lewis (1936) find out that supports the inheritance explanation with the biological approach?

Answer 4

Found that 37% of his OCD patients had a parent with it, and 21% had a sibling with it.

Question 5

What is it called when there is a chance of you obtaining OCD from your family?

Answer 5

Concordance rate (agreement rate with familial members)

Question 6

What are the two genes that are suggested to play a role in OCD development?

Answer 6

SERT gene
COMT gene

Question 7

How does the SERT gene play a role in OCD?

Answer 7

A faulty copy of this gene causes serotonin to be re-absorbed too quickly by the nervous system, meaning it cannot play its normal role in blocking impulsive messages in the brain.

Question 8

How does the COMT gene play a role in OCD?

Answer 8

It has been shown that faulty copies of this increase the amount of dopamine in the Limbic system which increases the amount of anxiety a person has. The increase anxiety drives the obsessions a person with OCD has.

Question 9

Define polygenetic

Answer 9

More than one gene contributing to a disorder

Question 10

What did Taylor (2013) to do support the genetic explanations?

Answer 10

Analysed the findings of previous studies and found evidence for 230 different genes playing a role in the disorder with many of the genes affecting serotonin and dopamine.

Question 11

What is the scientific name for identical twins?

Answer 11

Monozygotic

Question 12

What is the scientific name for non-identical twins?

Answer 12

Dizygotic

Question 13

What did Nestadt et al. (2005) find regarding OCD with twins?

Answer 13

Reviewed twin studies published on OCD and found that 68% of identical twins shared OCD and 31% of non identical twins shared it, suggesting that there is a strong genetic component.

Question 14

What did Marini + Stebinicki (2012) look at and find out regarding OCD with family members?

Answer 14

They looked at how common it was for two members of the same family to have OCD and found that it does seem to run in families.

Question 15

What did Cromer et al. (2007) extend with regarding OCD and what can this suggest?

Answer 15

They found that over half of the patients with OCD had experienced a severe trauma in the past, the more severe it was the worse the symptoms of OCD.
This suggests genes interact with the environment to trigger OCD and influence its severity.

Question 16

What are the characteristics of Neural Explanations?

Answer 16

Genes associated with OCD help to control and modulate the activity of neurotransmitters.
These explanations include both neurotransmitters and neuroanatomy
They overlap in many ways as different parts of the brain have different concentrations of neurotransmitters

Question 17

What is the neural explanation regarding serotonin?

Answer 17

This is a neurotransmitter that helps to regulate mood by preventing impulsive thoughts from spreading across the brain. Low levels of this have been found in the frontal cortex and have been linked to the inability to stop the obsessions. However, some people with OCD have normal SERT genes, meaning there are other causes of OCD.

Question 18

What is the neural explanation regarding dopamine?

Answer 18

Increased levels of dopamine have been found in the thalamus, part of the limbic system, and has been linked to an increase in anxiety.

Question 19

What is the neural explanation regarding changes in the way that the frontal lobe is functioning?

Answer 19

The frontal lobe forms part of the worry circuit, along with the limbic system. If the worry circuit is not controlled by the frontal cortex then anxious thoughts can spiral out of control.

Question 20

What does the parahippocampus gyrus do and how does it function with some OCD patients?

Answer 20

It plays a role in processing unpleasant emotions and has been found to function abnormally in some OCD patients

Question 21

What is the final neural explanation to do with multiple brain areas?

Answer 21

Multiple brain areas are involved with OCD and the genes interact with both the brain areas and the associated neurotransmitters.

Question 22

What did Nedstadt et al. (2010) find regarding one of the best treatments for OCD being antidepressants?

Answer 22

They found that OCD symptoms are common in other illnesses where there has been damage to the neurotransmitter systems.

Question 23

Define gyrus

Answer 23

These are the bumps on the brain

Question 24

Define Salcus

Answer 24

These are the dips on the brain

Question 25

Define cortex / lobe

Answer 25

This is the outer layer of the brain

Question 26

What is the main issue with the serotonin explanation regarding OCD?

Answer 26

50% of people with OCD also have clinical depression, which is also linked to low levels of serotonin. Therefore, the low levels of serotonin seen in OCD might be due to the comorbid disorder of depression, not the OCD itself.

Question 27

What did Pichichero (2009) find out regarding child cases of OCD? (2 things)

Answer 27

Found that a significant number of US child cases had suffered from an infection of strep throat shortly before developing symptoms of OCD. Also found that they developed Tourette’s which is a separate disorder with issues in similar parts of the brain as OCD. Suggests that damage to the nervous system by a virus can explain OCD

Question 28

What did Fallon and Nields (1994) find out regarding people being infected with Lyme’s disease?

Answer 28

Found that 40% of people who were infected by Lyme’s diseases ( bacterial infection caused by ticks) went on to suffer from neural damage which resulted in OCD

Question 29

What did Saxena + Rausch (2000) find evidence for and what is the advantage of using these?

Answer 29

Found consistent evidence for the role of the frontal cortex in OCD through PET, fMRI, MRI studies. Several different techniques being included presents stronger evidence and suggests that brain areas are involved with the disorder.

Question 30

What does MRI stand for?

Answer 30

Magnetic resonance imaging

Question 31

What fMRI stand for?

Answer 31

Functional magnetic resonance imaging

Question 32

What is another main issue with the biological explanations to OCD regarding correlations?

Answer 32

Much of the research is based on correlations which cannot provide causal explanations. Links can only be made between biology and OCD, and there is no cause and effect. Would be too unethical to run experiments due to chance of causing possible damage to ppt’s brain

Question 33

What is the very simplified explanation of the interaction between dopamine and serotonin?

Answer 33

Too much dopamine drives anxiety in the limbic system which increases the anxiety felt in the worry circuit. The frontal cortex has lower than usual serotonin and this means that the impulsive thoughts and anxiety cannot be inhibited (controlled)

Question 34

What is the alternative explanation, instead of the biological approach to OCD?

Answer 34

The cognitive approach which involves faulty thoughts that a person has

Question 35

What did Rachman and Hodges (1987) find which supports the alternative explanation, cognitive approach, to OCD?

Answer 35

Found that OCD patients had increased cognitions related to their OCD + that these were based in the frontal cortex— suggests a link between biology and the obsessions an OCD patient has.

Question 36

What is the diathesis - stress hypothesis regarding the biological approach to OCD?

Answer 36

People are born with a genetic / biological risk for OCD that environmental experiences, learning an cognitions play a role in the specific symptoms a patient suffers from/

Question 37

What is the name for the cognitive and biological combined approach?

Answer 37

Cognitive neuroscience

Question 38

Define diathesis

Answer 38

Genetic predisposition

Question 39

Define stress in the ‘diathesis stress model’

Answer 39

The environmental stimuli that triggers something