Topic Summaries

Biological approach

A-Level > Psychology > AQA > A-Level Psychology Topic Summaries > Clinical psychology and mental health > Biological approach
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Addiction

  • The biological approach to explaining OCD:
    • Genetic explanations:
      • Candidate genes: certain genes are linked with vulnerability to OCD (e.g.the SERT gene affecting serotonin transport, COMT gene affecting dopamine regulation, 5HT1-D beta which affects the efficiency of serotonin transport across the synapse).
      • Polygenic: OCD is not caused by a single gene but multiple genes. Each gene only increases risk slightly. 👥 Taylor (2013) discovered that OCD is polygenic which means that 230 different genes are involved in its development.
      • Aetiologically heterogeneous: different gene combinations may lead to different types of OCD (e.g.hoarding vs.contamination).
      • Family and twin studies: the higher concordance rates for OCD in identical (MZ) twins than non-identical (DZ) twins suggests genetic influence, though this rate is not 100%. 👥 Lewis (1936) found that of his OCD patients, 37% had parents with OCD and 21% had siblings with OCD.
    • Neural explanations:
      • Neurotransmitters: low serotonin activity leads to impaired mood regulation, which is linked to OCD. High dopamine activity is also associated with compulsive behaviours.
      • Brain circuits: overactivity in the basal ganglia and orbitofrontal cortex is linked to repetitive thoughts and compulsions. Thalamus hyperactivity may reinforce compulsive checking behaviours.
    • The biological approach to treating OCD:
      • The main drug treatments used are selective serotonin reuptake inhibitors (SSRIs) which prevent the reuptake and breakdown of serotonin on the pre-synaptic neuron. This leads to an increase in the concentration of serotonin in the synapse and therefore the post-synaptic neuron is constantly stimulated.
      • Tricyclics have a similar effect but are mainly used for people who don’t find SSRIs effective or have bad reactions to them. They increase the concentration of noradrenaline neurotransmitter in the brain.
        • Drug therapy can cause very bad side effects: patients taking clomipramine can suffer from side effects such as tremors, fatigue, aggressiveness, and weight gain.
        • Drug therapy and the economy: when people start being treated by drugs, they are less likely to miss days of work as they have more of a grasp on their condition compared to if they are unmedicated.

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