Biological approach to explaining OCD

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    Created by
    merve k

    Cards (7)

    • Genetic explanations
      • Candidate genes, e.g 5HT1-D: specific genes which create a vulnerability for OCD. -Serotonin genes are implicated in transmission of serotonin across synapses -Dopamine genes also implicated in OCD and may regulate mood. (Both are transmitters).
      • OCD is polygenic: caused by several genes. Taylor (2013) found that up to 230 different genes may be involved in OCD.
      • Different types of OCD: aetiologically heterogenous. There is also evidence that different types of OCD may be result of particular genetic variations.
    • Neural explanations
      • Low serotonin lowers mood: if a person has low levels of serotonin then normal transmission of mood relevant info does not take place and mood is affected.
      • Decision making systems in frontal lobes impaired.
      • Parahippocampal gyrus dysfunctional: functions abnormally in OCD.
    • ++ Evidence for the genetic explanation of OCD. Nestadt et al. (2010) reviewed twin studies, found 68% of MZ twins shared OCD, opposed to 31% of DZ twins. This means that people who are genetically similar are more likely to share OCD, supporting a role for genetic vulnerability.
    • --Existence of environmental risk factors. Genetic variation affects vulnerability to OCD, but there are also environmental risk factors that trigger or increase the risk of OCD. Cromer at al. (2007) found half of the people with OCD in one sample had experienced a traumatic event. This means that genetic vulnerability only produces a partial explanation for OCD.
    • --Animal studies show particular evidence is associated with repetitive behaviours in other species. However, the human mind is much more complex so may not be possible to generalise from animal repetitive behaviour to human OCD. This means that animal studies of candidate genes are probably not relevant to understanding OCD.
    • ++ Supporting evidence for the neural model. Antidepressants that work on serotonin also reduce OCD symptoms. This means that biological factors are more likely to be involved in OCD.
    • --There is no unique neural system. Many people with OCD also experience depression. It could simply be that serotonin activity is disrupted in many people with OCD because they are depressed as well. This means that serotonin may not be relevant to OCD symptoms.