Biological explanation of OCD

Question 1

Genetic explanation:
Candidate gene (e.g 5H1T - D)

Answer 1

• identified genes causing vulnerability to OCD
• Seratonin gene (5H1T - D) involved in transmission of serotonin across synapse
  (dopamine gene also implicated)

Question 2

Genetic explanation:

OCD = polygenic

Answer 2

• no single gene, several genes

- Taylor, evidence up to 230 different genes involved

Question 3

Genetic explanation:

different types of OCD

Answer 3

• genes cause OCD in some, not others

- aetiologically heterogeneous, types of OCD caused by genetic variation (such as hoarding)

Question 4

Neural explanation:

low levels of serotonin lowers mood

Answer 4

• neurotransmitters responsible for relaying between neurons (low serotonin stops transmission, relevant info does not take place, mood affected)

Question 5

Neural explanation:

decision-making system in frontal lobe impaired

Answer 5

• some causes of OCD (hoarding) associated with impaired decision making
• association with abnormal function of the lateral frontal lobe
• front lobe responsible for logical thinking and decision making

Question 6

Neural explanation:

Parahippocampal gyrus disorder

Answer 6

• associated with processing unpleasant emotions