Treatments of Scizophrenia

• What neurotransmitter is affected in Schizophrenia?

  Dopamine
• How are the levels of dopamine affected in Sz?

  they are high
• How can we explain the heightened level of dopamine in Sz?

  More receptors, dopamine receptors fire more quickly, drugs need to lower the levels
• Drug therapy is seen as more effective than any other form of therapy in the treatment of schizophrenia. The majority of Sz patients will follow drug treatment - these drugs come under the category of anti-psychotics.
• There are 2 main types of anti-psychotics: typical (conventional drugs) an atypical
• What effect to agonist drugs have?

  increase the levels of neurotransmitter e.g. SSRI for serotonin/ amphetamine for dopamine
• What effect do antagonistic drugs have?

  Decrease levels of neurotransmitter e.g. L-Dopa for Parkinson's
• Notes on typical drugs:

  1. discovered in 1950s
  2. block dopamine within 48 hours
  3. most frequently given = chlorpromazine
  4. reduce positive symptoms - delusions and hallucinations
  5. taken in tablet form 2-4x a day
  6. doesn't cure negative symptoms
  7. bind to dopamine receptors (particularly D2 receptors) permanently and block their action
  8. by reducing the stimulation of the dopamine system in the brain, antipsychotic drugs can eliminate hallucination and delusions.
  9. effectiveness of these dopamine antagonists lead to the dopamine hypothesis
• Notes of atypical drugs:

  1. newer - discovered in 1990s
  2. block dopamine and serotonin receptors
  3. e.g. clozapine and rispendone
  4. tablet form 2-4x a day
  5. temporarily bind to receptors
  6. in the same way that typical/conventional antipsychotics bind to D2 receptors, but rather than permanently blocking the dopamine action, they temporarily bind to receptors and the rapidly dissociate to allow normal dopamine transmission. This reduces side effects
  7. combat positive and negative symptoms
• Lieberman researched over 1000 patients taking antipsychotic drugs and found that 74% of patients discontinues their treatment within 18 months due to intolerable side effects - drugs not very useful, people do not finish their treatment plans - don't work for everyone - high relapse rate - not a long lasting treatment - drugs only treat symptoms not the cause
• Research has shown that 55% of those on typical antipsychotics suffered relapses, compared to 42% of patients on atypical antipsychotics - atypical more effective at long term treatment - people lass likely sto stop taking them due to side effects
• Meltzer reported that atypical antipsychotic clozapine was more effective than typical and other atypical drugs and it had been used effectively for those who had not responded well to typical antipsychotics - atypical drugs implied to be more effective - clozapine the most effective
• Sampath et al studied patients who had taken typical/conventional drugs for 5 years. One group switched to a placebo, the other group continued taking the drugs. In the placebo group, 75% relapsed within 1 year, compared to 33% who continued taking the drug. - drugs are effective to a certain level, do not work/have the same effect for everyone. Typical drugs better than nothing

  have the 25% been cured

  25% - drugs not doing anything for them - something else causing their Sz

  if dopamine was the pure and only cause - 100% of placebo group should have relapsed.