Psychology - Biological Schizophrenia

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Genetic Factors

Family Studies

  • S - Schizophrenia may be passed down through genes
  • E - Gottesman (1991) studied 20 pairs of twins and found the concordance rate for monozygotic twins to be around 48% and 17% for dizygotic twins.
  • E - This shows that the stronger the genetic link the stronger the chance of having schizophrenia is. 
  • L - This supports the idea that schizophrenia is linked by genetics.
  • S - Evidence supports genetics factors to schizophrenia. 
  • E - Tienari studied 164 adopted children who's biological mothers had schizophrenia. They had a concordance rate of 6.7% compared to 1% in adopted children without schizophrenic parents.
  • E - This shows strong evidence for genetics as there's no social or environmental influences; it shows a direct genetic link.
  • L - This strongly supports the role of genetics in schizophrenia.  

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Genetic Factors - Extra Evalutation

  • S - Psychology as a science is disputed within these studies.
  • E - Concordance rate is not 100% within these genetic studies. 
  • E - This means that the rest of the percentage must be down to other factors, meanning that genetics are not the only part to play in schizophrenia. 
  • L - This indicates that schizophrenia is not totally down to genetics. 
  • S - There are issues with twin studies.
  • E - Twins aren't able to represent the wider population.
  • E - There are very few monozygotic twins in the population, and only 1% are schizophrenic, meaning the results of these studies cannot be extrapolated to the wider population. 
  • L - This poses issues for supporting genetics in terms of schizophrenia. 
  • S - Adoption studies don't clarify the situations enough.
  • E - The children may have been exposed to the biological schizophrenic parents as it's not certain what age they were adopted at. 
  • E - This means that environmental and social factors may have been involved, weakening the validity of the studies as it's not a straight genetic link.
  • L - This shows issues in adoption studies in supporting genetic links for the development of schizophrenia. 
  • Were they diagnosed with the same diagnostic material? Determinist and reductionist. 
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Biochemical Explanations

Biochemical explanations are down to the dysfunction of the neurotransmitters: dopamine, serotonin and glutamate.

The Dopamine Hypothesis

  • Schizophrenia is caused by an excess of DA (dopamine) activity either in terms of too much of it being released or there being too many receptors (particularly D2).
  • This causes the brain to function abnormally and become depentend on dopamine, thus causing schizophrenic symptoms. Depending on where the excess of dopamine is different symptoms are shown, when in the mesolimbic pathway results in positive symptoms such as hallucinations and the mesocortical system resulting in negative symptoms such as affective flattening. 
  • The excess may be a result of there being no/little enzymes to destroy spare neurotransmitters that don't find their receptors. Too much dopamine can result in transmitters can leap to other receptors in a different area causing mixed messages, meaning that the person can become confused and mixed up resulting in schizophrenic symptoms. 
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Biochemical Evaluation

  • S - Evidence supports the biochemical explanation to schizophrenia.
  • E - People with parkinsons disease have low levels of dopamine; they're give L-dopa to increase their levels. People who take this sometimes develop schizophrenic symptoms if they take too much L-dopa to help their parkinsons. 
  • E - This shows that an excess of the neurotransmitter dopamine causes schizophrenia.
  • L - This supports the dopamine hypothesis in terms of schizophrenia. 
  • S - Biological research supports the dopamine hypothesis.
  • E - Falkai et al (1988) found that in autopsies those with schizophrenia had a larger amount of dopamine receptors than usual. 
  • E - This suggests that abnormal dopamine functions are evident in schizophrenics.
  • L - This supports the dopamine hypothesis in terms of abnormal functioning being the cause of schizoprenia. 
  • S - Knowing this can be helpful in terms of application.
  • E - Brain scans can be done to determine whether someone has signs of abnormal dopamine functionings.
  • E - This means schizophrenia can possibly be found at an earlier stage and treatment can be made available. 
  • L - This means practical applications can be made through this approach. 
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