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schizophrenia evaluation - Coggle Diagram
schizophrenia evaluation
strengths
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using controls: made sure questionairre was more accurate to see if it did not elicit feelings of persecution
qualitative AND quantitative data: both were used in study, including semi structured interview, allowing for detailed understanding of perescutory ideation AND statistical analysis provided by quantitiatve data.
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weaknesses
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lack of generesablity: sample was relatively small and loimited to UK univerisity, making it less represnatative
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EXPLANATIONS:
BIOLOGICAL
GENETIC:
familty studies: One is more likely to inherit schizophrenia when a first degreee relative (parents generally) / close relative has the same disorder.
gottsman found thaat the likelihood of having schizophrenia went up from 1% to 48% in the gen popoulation when you have a twin with schizo.
twin studies : two types, momozygotic and dizygotic. Mono zygotic twins share 100%dna while dizygotic twins share only 50% of DNA. KEY TERM: CONCORDANCE.
Concordance: likelihood of inheriting the gene that has the disorer in it. Concordance rate of schizophrenia is higher in momozygotic than dizygotic twins.
Hilker et al- carried out twin study looking at not only those with schizo diagnosis but also those with related disorders and found that the heritability of schizo was 79%.
adoption studies looking at similarities between an adoptive indivd=uals and their biological parents as a way of distinguishing the influence of gentics and environment . :
Tienari et al - found that adoptees with a biological mother who has been diagnosed with schizophrenia are more likelty to develop the same disorer. In line with family studies there is a genetic influence in the devlopment of schizpphrenia
BIOCHEMICAL: DOPAMINE HYPOTHESIS - states that dopamine is produced in hgiher amounts in those with schizphrenia. It links positive symptoms of schiophrenia and excessive amounts of dopamine. FOR EXAMPLE, excessive dopamine production can cause swelling in the brocas region of the brain, which is responsible for the formation of language, and therefore when this sweling happens- it causes thought disorer- which is a positive symptom of schizphrenia.
DRUG TRIALS- drugs that increase levels of dopamine are amphetamines and cocaine (already in your brain macha). Increase of dompanie is correlated to increase in halccuinations and delusions. High doses of syntethic, unnatural dopamine caused by drugs such as cocaine, amphetiamine and L DOPA can foster postivie symptoms of schizphrenia.
For example, patiients with parkinsons disease use L DOPA. However, too much of that drug can cause symptoms that are present in a schizphrenia diagnosis such as hallucinations
POST-MORTEM STUDIES- studies done on deceased individuals with schizophrenia have shown that they have a larger number of dopamine receptors than those without sz.
Wise et al found that brain fuild from dead patients had abnormally low levels of enzymes that breaks down the dopamine thorugh the dopamine receptor, suggesting that dopamine may have been prsent in excessive quantities within the receptor.
PET SCAN - positron emmision tomography. A scan thatuses gamma camerasto detect radioactive tracers such as glucose that is injected in blood. They measrue the amounts of dopamine activity in brain and indicate that in certain areas of the brain there are greater number of dopamine receptors in those with sz than those without. These excessive dopamine activities are linked to positive symptoms.
Research suggests that increase in dopamine activity in areas like the prefrontal cortez of those with sz may correlate with negative symptoms such as falttened affect.
PSYCHOLOGICAL
COGNITIVE- while it recognizes that bilogical factors contribute to the positive and negative synptoms of sz, it suggest that symptoms of sz do not solely rely on physiological explanantions only, such as role of biochemicals and genetics. It rather suggests that it could be due to faulty mental proccesses.
FRITH ET AL descirbes sz as abnormality of self monitoring. What is this? it is when those with sz fail to recognize that their perceived hallucinations are just in fact their inner speeches (cannot tell reality apart from their hallucinations). leads them to attribute what they're hearing to someone else. This was ibvestiagted by asking participants whther items that had been read out loud where from their own head r from an experiemnter, or an external source like a computer. He found that patients with incoherent speech performed worst at the task. Becuase of their incoherent speech, this si being linked to attention and memory difficulty- crucial for self moitoring.
Misinterpreation of perception - those being able to differentiate theri self generated though from an external source use logical reasoning to theri hallucainations. However, those with sz are unable to do this. People with sz always believe their self generated thought are coming from an external source and not from within, and eventually it becomes incorporated within their set of beliefs. Failure to regulate these thoughts can lead to delusions of alien control and auditory hallucantions. this can also lead to delusions of paranoia and incoherence.
final psychological explanation - those experiencing negative symptoms such avoltion have difficulty generationg spontanoues actions such as starting a conversation but are able to respond to a stimulus. This may arise due to impaired theory of mind .