explaining OCD - biological approach

Question 1

How do genetics explain OCD?

Answer 1

• mental disorders can be inherited genetically from parents

What are the 3 key points in the genetic explanation for OCD?

• the COMT gene
• the SERT gene
• Diathesis-stress

Question 2

What is the COMT gene?

Answer 2

• the COMT gene produces COMT which regulates the production of the neurotransmitter dopamine
• one variation of the COMT gene is more common in OCD patients, this variation creates high levels of dopamine and lower activity of the COMT gene

Aka: higher dopamine levels=potential OCD

Question 3

What is the SERT gene?

Answer 3

• SERT gene affects the transport of serotonin which creates lower levels of the neurotransmitter serotonin

AKA lower levels of serotonin=potential OCD

Question 4

What is diathesis-stress?

Answer 4

• complex behaviours cannot be caused by one simple gene
• implications in the SERT gene also contribute to other disorders such as depression, so it doesn’t directly cause OCD

THIS SUGGESTS:

- each gene only creates a VULNERABILITY (a diathesis) for OCD as well as other disorders 
Other factors ('stressors')/triggers will determine which/or if a disorder occurs

Question 5

(+) How have animal studies shown that higher levels of dopamine is associated with OCD symptoms?

Answer 5

Szechtman et all - drugs that induced higher levels of dopamine resulted in animals having stereotypical OCD movements/behaviour

Question 6

How are neural explanations associated with OCD?

in regards to the caudate nucleus

Answer 6

• the caudate nucleus which usually control’s worrying signals and suppresses minor signals that aren’t potentially harmful/serious - when damaged it fails to suppress minor worries from the OFC so sends them to the thalamus

(+) brain scans show that when OCD patients who have germ obsessions are faced with dirty cloths their OFC activity is heightened

Question 7

Evaluation of the biological explanation to OCD

Answer 7

(+) Nestadt - explanation supported by studies on relatives of OCD sufferers, if individuals had first-degree relatives with OCD they were 5 times more likely to also have OCD at some point in their lives
(-) Gene implications (SERT, COMPT) are not specifically associated to OCD, can contribute to other illnesses
(-) because OCD causes are more complicated that a simple gene-disorder relationship, people may be lulled into thinking there’s a simple solution, which is false hope