Explaining OCD - Biological Approach

Question 1

Obsessive Compulsive Disorder

Answer 1

Classed as an anxiety disorder, characterised by obsessive thinking and repetitive behaviours

Question 2

Obsessions

Answer 2

Internal components because they are intrusive thoughts (something you think)

Question 3

Compulsions

Answer 3

External components because they are repetitive behaviours (something you do) - these reduce anxiety

Question 4

Biological Explanations

Answer 4

• Sees psychological illness as caused by abnormal psychological processes
• Two main explanations:
• Neural: occurrence of OCD through abnormal functioning of neural (brain) mechanisms and neurotransmitters
• Genetics: hereditary influences through genetic transmissions from parent to offspring

Question 5

Genetic Explanations: COMT

Answer 5

• Produces enzyme that degrades dopamine
• Low activity variant (allele) of this gene in OCD patients
• Impaired ability to degrade dopamine leads to higher levels in synapse
• Particularly after stress
• Dopamine = stress hormone

Question 6

SERT (5-HTT)

Answer 6

• Produces protein that transports serotonin (which reduces stress) back to the presynaptic membrane (reuptake)
• High activity variant (allele) in OCD patients
• Serotonin removed too quickly = lower levels received, shorter duration of effects

Question 7

Neurotransmitters and OCD

Answer 7

• Abnormal levels of neurotransmitters (high dopamine, low serotonin)
• Dopamine: Excitatory NT, reward/ movement/ memory, habit-forming in OCD
• Serotonin: Inhibitory NT, appetite/ behavioural impulse control/ mood, impulse control OCD

Question 8

Neuroanatomy of OCD: Orbitofrontal Cortex

Answer 8

Sends signal to the thalamus about things that are worrying - hypervigilance in OCD

Question 9

Neuroanatomy of OCD: Thalamus

Answer 9

Generates impulse to act and then stop activity when impulse lessens - controls motivation/ compulsion in OCD