OCD neural explanation

Question 1

Eval genetic explanation

Answer 1

• evidence from wide range of sources
• family and twin studies (but concordance rate not 100% so diathesis-stress model brings in nature and nurture) (maybe gene predisposes but environment can cause trigger)
• too many candidate genes (up to 230 and haven’t got a role for each gene yet)
• no predictive value for the disorder (we can’t predict what obsessive thoughts/ compulsions as too much variation)( can’t tell how it’s gonna manifest itself)
• culturally transmitted? SLT vicarious learning may observe and imitate someone in household with OCD so nothing to do with genes but environment

Question 2

Neural explanation
Role of serotonin

Answer 2

• NTs= relay info from one neurone to the other
• low levels of serotonin means normal transmission of mood-related info is not possible
• deficiency initiates faulty signalling from OFC
• high levels of dopamine = affect conc and linked to compulsive behaviour/ stereotypical movements ( so those affected inability to stop focussing on obsessive thoughts and repetitive behaviours)

Question 3

Role of OFC

Answer 3

• decision making
• personality
• movement
• impulse control
  (PET scans shown heightened activities in region when suffering)

Question 4

The worry circuit

Answer 4

-OFC notices something is wrong
-OFC sends signals to thalamus about things that are worrying me
-Caudate nucleus (basal ganglia) is in between and responsible for regulating signals from OFC = thalamus doesn’t get hyperactive (brake or pedal)
Brake-nothing to worry about sent back to thalamus and OFC
Pedal caudalnucleus damaged or abnormal cannot suppress the worry signals message sent back to OFC and full alert obsessive and overly anxious

Question 5

Evidence for the worry circuit

Answer 5

Severe OCD (cannot participate in society) have brain scans- heightened activity in those areas
-had surgery which disconnects the basal ganglia from the frontal cortex can reduce symptoms of severe OCD and seemingly has worked
(OCD is played out and has roles in many parts of the brain)

Question 6

Pigott et al. 1992

Answer 6

Antidepressant drugs that increase serotonin activity have been seen to reduce OCD symptoms

Question 7

Supporting Evaluation

Answer 7

• give animals induced behavioural symptoms with dopamine such as Parkinson’s and schizophrenia
• effective biological treatments solely target the serotonin system

Question 8

Opposing evidence

Answer 8

• neural mechanisms remain unclear studies have shown abnormal functioning in neural systems are associated with OCD but there is no one highlighted as consistently and undeniably)

Question 9

Other opposing evidence

Answer 9

• causation or correlation