weak areas

• Biological approach to OCD


  • Views biological factors as leading to OCD
  • Targets biological factors to treat OCD
• Serotonin


  A neurotransmitter linked to OCD, low levels are associated with OCD
• How SSRIs work


  1. Blocking reabsorption of serotonin

  2. Increasing levels of serotonin in the synapse

  3. Repeated stimulation of receptors on post-synaptic nerve ending

  4. Higher levels of serotonin
• Neurotransmitters


  Pass information (messages) from one neuron to another
• Dopamine


  • High levels linked to OCD
  • Involved in experiencing pleasure, motivation and compulsions
• Serotonin


  • Low levels linked to OCD
  • Regulates mood, anxiety and memory
• Orbitofrontal cortex (OFC)


  • An area of the brain implicated in OCD
  • Sends signals to the thalamus about worrying things
• Basal ganglia


  • If damaged, fails to stop minor worry signals and the thalamus is alerted
  • Activates brain circuit that causes obsessions and compulsions
• PET scans show heightened activity in the OFC when a sufferer has active OCD symptoms
• Ash evidence supports the research to suggest the effectiveness of SSRIs and the biological approach to treating OCD
• The biological approach to treating OCD: Drug therapy

  1. Targets biological factors

  2. A low level of serotonin has been linked with OCD

  3. Medication which acts on the neurotransmitter serotonin is used to treat OCD

  4. Increasing serotonin causes the OFC to function at more normal levels (the worry circuit)
• Serotonin


  Neurotransmitter released from the pre-synaptic nerve ending
• Selective Serotonin Reuptake Inhibitors (SSRIs)


  • Anti-depressants
  • Originally designed to treat depression
  • Also found to be effective at treating OCD
• Fluoxetine (Prozac)


  • The most common SSRI used in adults
  • Works by increasing the levels of serotonin in the synapse
  • Can take 3-4 months to reduce symptoms as neurotransmitter levels rise gradually
• How SSRIs work


  1. Pre-synaptic cell sends information via a synapse

  2. Neurotransmitters (serotonin) released into the gap

  3. Receptors on post-synaptic cell recognise neurotransmitters and pass on the message

  4. 90% of neurotransmitters are reabsorbed by the sending cell (reuptake)

  5. SSRIs stop the reuptake of serotonin, meaning it stays in the synapse longer

  6. This leads to repeated stimulation of receptors on post-synaptic nerve ending and higher serotonin levels
• Different drugs work differently for different people
• Serotonin-Noradrenaline Reuptake Inhibitors (SNRIs)


  • Anti-depressants
  • Work on two neurotransmitters: serotonin and norepinephrine (noradrenaline)
  • Used for patients who do not respond to SSRIs
  • Increase amount of serotonin and noradrenaline in the synapse by slowing brain's breakdown of the two neurotransmitters
• Neural explanations


  Focus on what is happening in the brain
• Neural explanations


  • Can be influenced by genetics, brain damage, infection and the environment
• Neurotransmitters


  Pass information (messages) from one neuron to another
• Key neurotransmitters in OCD


  • Serotonin
  • Dopamine
• Dopamine


  High levels are linked to OCD, involved in experiencing motivation, rewards and compulsions
• Increased dopamine from completing compulsions


  Stops the anxiety associated with obsessive thinking
• Serotonin


  Low levels are linked to OCD, regulates mood, anxiety, and memory
• Antidepressant drugs that increase serotonin have been found to reduce OCD symptoms</b>
• Orbitofrontal cortex (OFC)


  An area of the brain implicated in OCD, sends signals to the thalamus about worrying things
• Brain circuit involved in OCD


  1. Basal ganglia (caudate nucleus) fails to stop minor worry signals

  2. Thalamus is alerted

  3. Impulses brought to attention

  4. Causes behaviour to address the impulse
• In OCD, the brain has difficulty stopping/ignoring impulses from this circuit, so the behaviour and obsessions continue
• PET scans show heightened activity in the OFC when a person with OCD has active symptoms