biological approach to explaining and treating OCD

• genetic explanations for OCD

  candidate genes, OCD is polygenic
• candidate genes

  researchers have identified genes that create vulnerability for OCD - 230 possible candidate genes

  many genes influence the functioning of neural systems in the brain
• OCD is polygenic

  • OCD is not caused by one single gene but a combination of genetic variations that together significantly increase vulnerability
  • Taylor analysed findings of previous studies and found that up to 230 different genes may be involved in OCD
• two genes thought to be involved in OCD

  SERT - affects the transport of serotonin causing lower levels of serotonin

  COMT - associated with the production of dopamine leading to irregular dopamine levels
• give one strength of genetic explanations for OCD

  RESEARCH SUPPORT

  . found 68% of MZ twins shared OCD in comparison to 31% of DZ twins

  . first degree relatives have a 10 % concordance rate

  . MZ twins have a 68 % concordance rate

  . DZ twins have a 31 % concordance rate

  . suggests that there must be some genetic influence on the development of OCD

  . research increases the validity of the theory

  . twin studies tend to use large samples which results in robust quantitative data therefore had good reliability
• name one limitation of genetic explanations for OCD

  DOESN'T INCLUDE ENVIRONMENTAL FACTORS

  . there is strong evidence for the idea that genetic variation can make a person more or less vulnerable to OCD

  . however, OCD is not entirely genetic in origin and environmental factors can have an influence in the risk of developing OCD

  . Cromer - found over 50% of people with OCD had experienced a traumatic event and OCD was more severe in those who had experienced trauma

  . suggests genetics is only a partial explanation for OCD

  . therefore the diathesis stress model may be a more valid explanation for OCD
• neural explanations for OCD

  the genes associated with OCD affect the levels of key neurotransmitters

  • suggests that abnormal levels of neurotransmitters are implicated in OCD
  • suggests that particular regions of the brain - basal ganglia and orbitofrontal cortex are implicated in OCD
• neural explanations for OCD - neurotransmitters

  . low levels of serotonin are linked to OCD - serotonin regulates mood and emotions and low levels may lead to increased anxiety and repetitive behaviours

  . dopamine: high levels of dopamine activity is thought to contribute to compulsive behaviours
• neural explanations for OCD - brain structures

  . worry circuit: set of brain structures including the orbitofrontal cortex and basal ganglia system - communication between these structures in the worry circuit appears to be overactive in people with OCD

  . in normal functioning, the basal ganglia can filter out minor worries from the OFC but if hyperactive even small worries get to the thalamus which is then passed back to the OFC, forming a loop of recurring obsessive thoughts
• name one strength of neural explanations for OCD

  RESEARCH SUPPORT:

  • antidepressants that work purely on serotonin are effective in reducing OCD symptoms suggesting serotonin may be involved in OCD
• drug therapy

  treatment involving drugs that have a particular effect on the functioning of the brain or some other body system
• what is the main drug used in the treatment of OCD?

  SSRIs
• explain how SSRIs work in the treatment of OCD

  . work on the serotonin system in the brain

  . inhibit the reuptake process in the synapse therefore serotonin is still present in the synaptic cleft and continues to stimulate to postsynaptic neuron

  . decreases anxiety by normalising the activity of the worry circuit
• combing SSRIs with other treatments

  . used alongside CBT

  . the drugs reduce a person's emotional symptoms meaning people can engage more effectively with CBT
• alternatives to SSRIs


  tricyclics - same effect on serotonin system with more severe side effects

  SNRIs - also increase noradrenaline levels
• name two strengths of drug therapy to treat OCD

  EVIDENCE FOR EFFECTIVENESS:

  . Soomro et al. reviewed studies that compared SSRIs to placebos in the treatment for OCD

  . all studies showed better outcomes with the SSRIs than placebos

  . therefore drugs appear helpful for most people with OCD

  
  

  COST EFFECTIVE + NON DISRUPTIVE:

  . cheap in comparison to psychological therapies - good value for NHS who have limited funding

  . non disruptive / non time consuming in comparison to therapy which involve time spent at therapy
• name two limitations of drug treatments for OCD

  SIDE EFFECTS:

  . most likely temporary however can be quite distressing for people - reduces quality of life

  SHORT TERM:

  . work while people are on them however if they stop taking drugs symptoms may come back meaning they have to take them for the rest of their lives