The biological approach to OCD

Question 1

How can the biological approach be used to explain OCD

Answer 1

1) genetic explanations

2) neural explanations

Question 2

list the genetic explanations of OCD

Answer 2

1) COMT gene
2) SERT gene
3) diathesis stress model

Question 3

what is the COMT gene

Answer 3

It is involved in the production of COMT which regulates the production of the neurotransmitter dopamine
This variation of the COMT gene has been found to produce lower activity of COMT and higher levels of dopamine which has been implicated within OCD patients

Question 4

What is the SERT gene

Answer 4

the SERT gene affects the transportation of neurotransmitter serotonin creating lower levels
These lower levels have been implicated with patients of OCD

Question 5

Describe the diathesis stress model

Answer 5

The idea that a simple link between genes and OCD is unlikely, this model suggests that each individual gene creates a vulnerability to the disorder and that other factors, such as the environment affect what condition develops.

Question 6

List the neural explanations to OCD

Answer 6

1) abnormal neurotransmitter levels

2) abnormal brain circuitry

Question 7

Explain how abnormal brain circuitry could be linked to OCD

Answer 7

1) the orbitofrontal cortex sends worry signals to the thalamus of the brain
2) the caudate nucleus supresses signals to the thalamus from the OFC
3) in OCD patients the caudate nucleus is damaged so minor worry signals aren’t supressed and reach the thalamus which in turn sends signals to the OFC creating a worry circuit
4) also seen in OCD patients is the OFC is over active as well as having a damaged caudate nucleus

Question 8

explain how abnormal levels of neurotransmitters could cause OCD

Answer 8

1) dopamine levels are thought to be higher in OCD patients- this is based on animal studies in which high does of dopamine caused stereotypical OCD patterns
2) serotonin levels are thought to be low in OCD patients which has been supported by drug research using antidepressants containing serotonin which reduced symptoms

Question 9

evaluate the biological approach to explaining OCD

Answer 9

1) support from twin and family studies
2) ignores alternative explanations
3) real life application in human genome mapping
4) research support for the role of the OFC

Question 10

evaluate the genetic explanations of OCD

Answer 10

1) research support from twin and family studies
2) challenging research= concordances rate not 100%
3) issue and debate= nature vs nurture
4) research methods = ethical implications of practical applications
5) practical application= mapping of the humane genome allowing identification of certain disorders present in foetus before birth allowing decision of abortion or not, also may allow a means of turning certain genes off so the disorder is not expressed

Question 11

evaluate neural explanations of OCD

Answer 11

1) supporting research = support for the role of the orbitofrontal cortex =MRI of patients and immediate family showed reduced grey matter in key areas of brain including OFC- supports that anatomical differences
2) challenging research = alternative explanations, phycological explanations ie the 2 process model, association of NS with UCS causes anxiety, this is then maintained via avoidance of anxiety provoking stimuli, obsession formed and link learned with compulsive behaviours such as hand washing to reduce anxiety
3) issue and debate = nature vs nurture
4) research methods= concordance rate never 100%

Question 12

How can antidepressants be used to treat OCD as a drug therapy

Answer 12

1) SSRI’s increase levels of serotonin in the blood by inhibiting the reuptake of serotonin from receptors, therefore increasing the level of activity within the synapse
2) tricyclics which block the transport mechanisms for the reabsorption of seratonin and noradrenaline into pre-synaptic cells after they have been fired increasing activity of the neurotransmitters in the synapse

Question 13

how can anti-anxiety drugs be used as a drug therapy to treat OCD

Answer 13

1) benzodiazpines (BZs) slow down the actovyt of the CNS by enhancing the actovoty of the neurotransmitter GABA.

it reacts with GABA receptors on the spot synaptic membrane. When GABA binds it opens channels allowing the influc of chloride ions which increases the difficulty of other neurons stimulating the neuron.

Question 14

Evaluate the biological approach to explaining OCD

Answer 14

1) supporting research = effectiveness supported using randomised control trials comparing drug to placebo . 17 studies using SSRI with OCD patients found them more effective at reducing symptoms up to 3 months after treatment
2) challenging research = not a lasting cure- maina et al found patients relapsed within a few weeks if medication is stopped, in a review of treatments of OCD suggested although it may be commonly used, psychotherapies such as CBT should be tried first- suggest drug therapy may take little effort and effective short-term, no lasting cure is provided
3) issue and debate= nature vs nurture
4) research methods= publication bias- evidence of a publication bias towards studies that show positive outcomes of antidepressant treatment causing an exaggeration of benefits. The strong interest of drug companies to continue with success of psychotherapeutic drugs causes a selective publication bias leading to doctors making inappropriate treatment decisions which may not be in the patients best interest