Biological Approach To Explaining And Treating OCD

Question 1

What are the two explanations for OCD?

Answer 1

-Genetic explanation.
-Neural explanation.

Question 2

What is the genetic explanation for OCD?

Answer 2

OCD can be inherited from genetics. If you inherit certain genes, you are predispositioned to have OCD.

Question 3

What is the diathesis-stress model?

Answer 3

A model that states that psychological disorders (e.g. OCD) are predisposed from inherent vulnerability AND are triggered by environmental stressors.

Question 4

What are the two genes in the genetic explanation of OCD?

Answer 4

-COMT gene.
-SERT gene.

Question 5

What does the COMT gene do?

Answer 5

It produces an enzyme that regulates the function of dopamine.

Question 6

What does a variation of the COMT gene result in?

Answer 6

It decreases the amount of COMT available.
Thus, dopamine levels are not controlled (as there are less enzymes), and there is too much dopamine.
-This causes hyperactivity. This gene variant is common with OCD patients.

Question 7

What does the SERT gene do?

Answer 7

It helps in the reuptake of serotonin.

Question 8

What does a variation of the SERT gene do?

Answer 8

This variation causes an increase in transporter proteins, resulting in less serotonin binding to receptors.
There is an increase in the reuptake of serotonin, causing lower levels.
-This causes anxiety. Low serotonin levels and a mutated SERT gene have been linked with OCD sufferers.

Question 9

What did Taylor (2013) discover about the genetic explanation for OCD?

Answer 9

Taylor (2013) identified up to 230 genes linked with OCD, suggesting that it is polygenic. OCD can be presented in different manners for different people, although they all have the same symptoms, such as obsessions and compulsions.
(e.g. one person can’t step on the cracks on the pavement, and one person needing to touch the light switch).

Question 10

What did Nestadt et al (2000) discover about the genetic explanation for OCD?

Answer 10

Nestadt et al (2000) found that people with first degree relatives who are OCD sufferers have a 5X greater risk of suffering from OCD.
-An additional twin study (2010) showed that OCD concordance rates for MZs are 68%, while the concordance rate is 32% for DZs.

Question 11

What did Billett et al (1998) discover about the genetic explanation for OCD?

Answer 11

Billett et al (1998) conducted a meta-analysis (a study that combines the results of similar studies) of 14 twin studies. On average, MZs are 2X more likely to develop disorders than DZs.

Question 12

What is a meta-analysis?

Answer 12

A study that combines the results of similar studies.

Question 13

What are strengths of the genetic explanation?

Answer 13

-OCD is polygenic (up to 230 genes can be responsible for the disorder).
-Experiments which inject animals with drugs that increase dopamine levels caused them to show OCD-like symptoms.

Question 14

What are weaknesses of the genetic explanation?

Answer 14

-Genes alone don’t determine who will develop OCD- they only create vulnerability.
-Evidence for concordance rates aren’t 100%, showing that OCD is based on other factors (Diathesis-Stress Model).

Question 15

What is the neural explanation for OCD?

Answer 15

Certain neurotransmitters and structures of the brain are associated with OCD.

Question 16

What is the frontal lobe of the brain responsible for?

Answer 16

Decision making and logical thinking.

Question 17

________ functioning or ________ of the frontal lobe is linked with OCD.

Answer 17

Abnormal, damage.

Question 18

Some cases of OCD are linked with impaired ________ ________.

Answer 18

Decision making.

Question 19

What does OFC stand for?

Answer 19

Orbitofrontal cortex.

Question 20

What does the OFC do?

Answer 20

It is involved in the cognitive process of decision making.

Question 21

What is the consequence of an overactive OFC?

Answer 21

It causes hyperactivity and intrusive thoughts for primal impulses.

Question 22

What is the basil ganglia responsible for?

Answer 22

Emotions & executive behaviours (hypersensitivity results in repetitive moments).

Question 23

What do PET scans show?

Answer 23

PET scans of OCD patients show heightened activity in the OFC.

Question 24

How does the OFC become overactive?

Answer 24

Normal: OFC sends warning signals, which are suppressed by the caudate nucleus.
OCD: caudate nucleus is damaged, so it can’t suppress the increasingly excited signals - causing compulsive behaviou & anxiety.

Question 25

How can surgery help with severe OCD symptoms?

Answer 25

Brain surgery that disconnects the basil ganglia from the frontal cortex.

Question 26

What is used to treat OCD?

Answer 26

Drug therapy (SSRI’s and BZ’s).

Question 27

What does SSRI stand for?

Answer 27

Selective Serotonin Reuptake Inhibitors.

Question 28

What does BZ stand for?

Answer 28

Benzodiazepines.

Question 29

What are SSRI’s?

Answer 29

Antidepressants that increase serotonin levels by preventing the reuptake of serotonin.

Question 30

What are BZ’s?

Answer 30

Drugs that reduces anxiety by enhancing GABA (a neurotransmitter which quietens neurones in the brain, by reducing stimulation) to slow the nervous system down.

Question 31

How do SSRI’s work?

Answer 31

They block the reuptake channel.
Serotonin’s activity is prolonged in the synaptic cleft, increasing the likelihood of it binding to receptors.
This increases serotonin levels in the brain, reducing anxiety symptoms.

Question 32

How do BZ’s work?

Answer 32

When a BZ binds to a receptor, it enhances GABA.
This calms neurones down by making it negatively charged (so it is less likely to fire).

Question 33

What are strengths to the neural explanation?

Answer 33

-Research support for its effectiveness. Drug trials (e.g. Soomro et al- 2008) with placebos prove so.
-Requires little input and effort, cheaper, and more economical for health services.

Question 34

What are weaknesses to the neural explanation?

Answer 34

-Drugs only treats the symptoms, not the cause. It leaves patients prone to relapse. Psychological treatments are a more long-term solution.
-Reductionist: the biological approach doesn’t take learning into account. OCD may be learnt through CC and maintained through OC.

[For example, dirt is associated with anxiety, and this is maintained through OC, where a person avoids dirt and continually washes their hands. This hand washing reduces their anxiety and negatively reinforces their compulsions].