Biological explanations for OCD

Question 1

What explains genetic explanations

Answer 1

Research from family and twin studies
tends to run in families suggesting a genetic link

Question 2

What were family studies into OCD

Answer 2

Lewis- 37% of OCD patients had parents with OCD and 21% had siblings with OCD

Question 3

What is the role of the sert gene

Answer 3

Abnormalities are linked in OCD
Involved in the transport of serotonin (low levels are implicated in OCD)
Ozaki et al- 2 families with mutations of the gene 6/7 family members had OCD

Question 4

What are neural explanations of OCD

Answer 4

Evidence from PET Scans shows abnormal functioning
-The orbifrontal cortex sends signals to the thalamus about worries which are usually suppressed by the caudate nucleus
-If the caudate nucleus is damaged the worry isn’t suppressed and the thalamus is alerted which confirms the worry to the OFC
-This creates a ‘worry circuit’

Question 5

Neurotransmitters and OCD

Answer 5

OCD is associated with low levels of serotonin and high levels of dopamine
Serotonin and dopamine abnormalities are implicated in the malfunction of the caudate nucleus

Question 6

Strengths

Answer 6

Lots of evidence that genes influence OCD
-Large scale review of twin studies shows concordance rates in MZ twins 63% and 31% in DZ twins

Question 7

Limitations

Answer 7

Diathesis stress model
Many different genes,

Question 8

Diathesis stress model

Answer 8

Genes only influence risk and so don’t determine if someone will get the disorder.

Question 9

Many different genes

Answer 9

Two OCD cases could have no similar genes or some people could have no risk genes and still have OCD. Limits the usefulness. Taylor found 230 genes.