abnormal neurotransmitter levels

• Neural correlates


  Abnormal neurotransmitter levels or abnormal brain structures
• Dopamine hypothesis


  Abnormal levels of the neurotransmitter dopamine can provide an explanation for schizophrenia
• Hyperdopaminergia in the sub-cortex (high levels of dopamine)


  Associated with the positive symptoms of schizophrenia (e.g., auditory hallucinations)
• Hypodopaminergia in the cortex (low levels of dopamine)


  Associated with negative symptoms such as avolition
• Schizophrenia patients can experience both positive and negative symptoms
• ao3 - research support(1)

  drugs that increase levels of dopamine worsen symptoms in people with schizophrenic and induce symptoms in people without

  demonstrates increased levels of dopamine activity lead to symptoms of schizophrenia
• ao3 - research support(2)


  contradictory: clozapine is the most effective drug at reducing symptoms of schizophrenia - acts on serotonin as well as dopamine implying other neurotransmitters play a role in developing schizophrenia

  this makes the dopamine hypothesis reductionist
• ao3 - direction of causation (1)

  antipsychotic drugs that reduce symptoms of schizophrenia do so by reducing dopamine activity

  strength of hypothesis as it suggests schizophrenia is linked to dopamine as altering dopamine transmission has a positive impact
• ao3 - direction of causation (2)

  contradictory: treatment fallacy proves to be an issue - just because dopamine blockers reduce symptoms, it doesn't mean that dopamine activity is the cause

  direction of causation is unknown and high dopamine levels could be a result of schizophrenia -> limitation as unclear whether abnormal dopamine activity are a cause or consequence (could be family/cognitive dysfunction)
• ao3 - individual differences

  dopamine abnormalities not present in every schizophrenic - especially those with negative symptoms

  dopamine abnormalities associated with positive symptoms and only explains certain aspects or types of the illness