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  • Created by: Darblu07
  • Created on: 19-05-16 10:04

The Biological Approach to Explaining OCD

  • Genetic Explanation
  • Genes are involved in individual vulnerability to OCD. 
  • Nestadt et al (2010) - 68% of identical twins shared OCD, as opposed to 31% of non-identical twins. 
  • OCD seems to be polygenic - not caused by one single gene but several genes are involved. 
  • Taylor (2013) - there are up to 230 genes involvement: possible candicate genes:
  • 5HT1-D gene - transport serotonin across synapse.
  • SERT gene - regulating serotonin, neurotransmitter > facilitates messages.
  • COMT gene - regulates production of dopamine.
  • If concordance rate for MZ twins is not 100% this suggest - other factors must be involved for cause of OCD
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The Biological Approach to explaining OCD

  • Neural Explanation
  • The perception of OCD as a result from abnormality functioning brain mechanism. 
  • OCD seems to be associated with impaired decision making which in turn may be associated with abnormal functioning of the lateral frontal lobe of the brain. 
  • Neurotransmitter are responsible for relaying information from one neuron to another.
  • If a person has low levels of serotonin then normal transmission of mood-relevant information does not take place - mental process may be affected.
  • The left paraphippocampal gyrus - associated with processing unpleasant emotions, functions abnormally in OCD.
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Biological Approach to OCD - Evaluation

  • Good supporting evidence
  • Nesdath et al - 68% identical twins = OCD. 31% non identical twins =OCD.
  • Some people are vulnerable to OCD as a result of their genetic make up. 
  • It strongly suggest that there is a genetic influence on OCD.
  • Too many gene candidate involved
  • Several genes are onvolved and that each genetic variation only increases the risk of OCD by a fraction.
  • Genetic explanation is unlikely to eve be very useful because it provides little predictive value. 
  • It isn't completely genetic.
  • Environmental factor are involved can trigger or increase the risk of developing OCD.
  • Cromer et al (2007) - OCD patients had a traumatic event in the past, OCD was more severe in those with more than one trauma. 
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Biological Approach to Treating OCD

  • Drug Therapy - aims to increase/decrease levels of neurotransmitter i the brain to increase/decrease their activity.
  • Drugs work in various ways to increase the level of serotonin in the brain.
  • SSRIs - work on the serotonin system in the brain. Serotonin released by certain neurons in the brain.
  • Neurotransmitter chemically conveys the signal from the presynaptic neuron to the postsynaptic neuron - it is reabsorbed by the presynaptic neuron where it is broken down and re-used.
  • Prevention of re-absorbtion and breakdown of serotonin SSRIs effectively increase its levels in the synapse.
  • Compensates for whatever is wrong with the serotonin system in OCD.
  • Takes 3-4 months of daily use of SSRIs to have impact on symptoms. 
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Biological Approach to treating OCD

  • Combination of SSRIs with CBT
  • Drugs reduce patients's emotional symptoms such as anxious or depressed.
  • Patients can engage more effectively with the CBT
  • Alternative to SSRI = SNRIs
  • Serotonin-noradrenaline reuptaake inhibitors. 
  • Clomipramine - second line of defence for patients who dont's respond to SSRIs.
  • SNRIs increase levels of serotonin as well as another different neurotrasmitter - noradrenaline.
  • SNRI has also been used to treat OCD in the last 5 years
  • Ha the same effect on the serotonin system as SSRIs.
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Biological Approach Treatment to OCD - Evaluation

  • Drug therapy tuckles OCD symptoms.
  • Clear evidence that SSRIs reduces the severity of OCD symptoms = improving the quality of life for OCD pateitns.
  • Soomro et al (2009) - compared SSRIs to placebos in treatment of OCD. = all 17 studies showed significantly better results for SSRIs than Placebos conditions.
  • SSRI's combined with a psychological treatment (CBT) is very effective.
  • Cost effectve and non-distruptive
  • Drug treatments are cheap compared to psychological treatments. 
  • SSRIs are non-disruptive to patient's lives as it declines sumptoms and does not engage with hard wok of psychological therapy. 
  • Many doctors and patients prefers drug treatments for these reasons.
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Biological Approach Treatment to OCD - Evaluation

  • Drugs can have side effects
  • Side effects such as indigestion, blurred vision and loss of sex drive are usually temporary.
  • Patients taking Clomipramine have common side effects = becoming aggressive and suffer disruption to blood pressure and heart rhythm. 
  • One OCD pateitns stop taking medication, it can have factors which reduces effectiveness of the drug therap.
  • In some cases, psychological therapies is better than drug therapy. 
  • Some cases, OCD follow trauma
  • OCD is widely believed to be biological in origin - standard of treatment should be biological
  • It is acknowledge that OCD can have a range of other causes in some cases, a response to a traumatic life event. 
  • If OCD is caused by trauma, drug treatment may not be appropriate.
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