The biological approach to explaining OCD

• how does the biological approach explain OCD

  ->it addresses both genetic and neural explanation

  ->genetic explanations suggests that OCD's inherited and that individuals receive specific from their parents which influences the onset of OCD

  ->neural explanations suggest that abnormal levels of neurotransmitters e.g serotonin an dopamine and certain regions of the brain are implicated in OCD
• genetic explanation of OCD

  ->genes are in the individual vulnerability of OCD

  ->Lewis (1936) observed that of his OCD patients that 37% had parents with OCD and 21% had siblings with OCD

  ->this suggests that OCD runs in families, although genetic vulnerability is probably passed from one generation to the next not the certainty of OCD
• Candidate genes 


  ->they are the genes that have been identified by researchers which create vulnerability of OCD

  ->these genes are in involved in regulating the development of the serotonin and dopamine system
• gene 5HT1-D beta


  ->it's implicated in the efficiency of transport of serotonin across synapses
• COMT gene


  ->it's associated with the production of an enzyme called catechol-O-methyltransferase (COMT) which regulates and breaks down/hydrolyses the neurotransmitter dopamine

  ->patients with OCD have this COMT gene, but it's faulty meaning the enzyme isn't produced and so it doesn't break down dopamine which results in higher dopamine compared to people without OCD
• SERT gene


  ->it affects the transport of serotonin hence (SERotonin Transporter)

  ->OCD patients have mutations in the SERT gene which causes transportation issues and cause lower levels of serotonin to be active within the brain

  ->Ozaki (2003) published results from a study of two unrelated families both have mutations of the SERT gene, it concluded with six out of seven of the family members had OCD
• since multiple genes 'candidate genes' play a role in the development of OCD, what does that say about the disorder

  the disorder is polygenic
• define the term polygenic

  ->OCD isn't caused by one single gene but that several are involved

  ->Taylor (2013) has analysed findings of previous studies and found evidence that up to 230 different genes may be involved in OCD

  ->genes that have been studied in relation to OCD include these associated the action of dopamine as well as serotonin, both neurotransmitters believed to have a role in regulating mood
• define the term of aetiologically heterogenous in terms of OCD


  ->it means that the aetiology of OCD has different causes (heterogenous)