discuss issues of reliability and validity associated with the classification and or diagnosis of
schizophrenia.
AO1 two types of classification systems:
- diagnostic and statistical manual (DSM) specific diagnostic criteria and a minimum of
two out of five key features for at least one month.
- Internal classification of disease (ICD), broader approach, stating that the clinical
picture is dominated by relatively stable, often paranoid delusions
To have a consistently accurate diagnosis, the systems must be valid and reliable
- validity is accuracy.
- Reliability is consistency.
Comorbidity is when an individual has the tendency of having more than one disorder at the
same time. For Example, an individual with schizophrenia may also develop depression at the
same time, and this increases the chance of misdiagnosis, undermining, validity and reliability.
Symptom overlap is when different disorder symptoms are shared and this leads to
misdiagnosis. For example, someone with schizophrenia might share symptoms of depression,
for example, avolition.
AO3 supporting research for comorbidity
- research found that 47% of patients diagnosed with schizophrenia also have diagnosis of
substance abuse
- 29% having an additional diagnosis of PTSD
- The most significant comorbidity rate of 50% was found with depression, running
alongside schizophrenia.
- Therefore, this suggests that these disorders may not be different disorders and we should
instead diagnose them as one disorder.
- This leads to the conclusion that the DSM and ICD are flawed.
Culture bias
- The average population of schizophrenics is 1%
- African Americans are nine times more likely to be diagnosed with schizophrenia in the uk
- However when research was conducted in Jamaica and Trinidad, it was found there’s only
a 1% likelihood therefore eliminating the idea of it being genetic in Afro Americans
Supporting research, suggests that validity and reliability are quite strong
- hollis in 2000 found a good correlation between symptoms of patients with schizophrenia
and the DSM criteria
- Jakobsen et al (2005) found a 98% inter-rater reliability amongst clinicians using the ICD’s
re-worked criteria, which appears to show that different doctors do reach highly similar
conclusions when drawing on the classification systems to diagnose the same patients.
- This suggests that the diagnosis is valid as the DSM enables doctors to diagnose people
However, research suggests the opposite.
- Study ‘on being sane in insane places’ 1973
- 2 Psychiatrists diagnosed the same patients using the DSM.
- Found that one diagnose 26 patience was having schizophrenia, whereas the other only
diagnose 13
- Suggest that interrater reliability is poor as their judgements were subjective and not
based on an objective and accurate criteria.
Discuss the biological explanation of schizophrenia
AO1 Genetics
- Inherited in DNA which runs in the family.
- The more similar the DNA the higher concordance rate
, - Therefore, there is a genetic predisposition, which is polygenic.
- 108 different genes seen in those with schizophrenia that both have many potential
genetic roots.
- Helps account for range of symptoms
Dopamine hypothesis
- initial theory: hyperdopaminergia
- Excesses receptors = increased activity
- Pos Symptoms include auditory hallucinations, which are caused from the
increased uptake in Broca’s area
- Later theory: hypodopaminergia
- Lowered dopamine activity
- The prefrontal cortex impacts thinking and decision-making, and this could lead to
avolition and the flat effect (neg)
Davies et al - concluded that it could be both of these theories as dopamine overall cause the
symptoms
AO3 genetics
research support of twin studies
- Found that the concordance rate is significantly higher for MZ twins compared to DZ twins.
- Kallman:
- Monozygotic twins - concordance rate up to 86%
- Dizygotic twins - concordance rate of only 15%
- This supports the idea that the more similar the DNA the higher the concordance rate.
- therefore suggest that predisposition is a key factor.
However, the interactionist position that biology and the environment play equal roles in
developing schizophrenia is a better approach.
- tienari et al 2004
- 19,000 Finnish children with biological mothers who had schizophrenia
- those place in adoptive homes, with childbearing styles, characterised by criticism were
more likely to develop schizophrenia (double bind theory)
- Furthermore, these children did not have a genetic risk factor, nor a pattern within them.
- The adopted children placed in highly critical homes, but did not have a biological mother
with schizophrenia did not have an increased risk of developing it.
- This strengthens the idea that a genetic exclamation assistant schizophrenia is most
convincing, only when used as part of the interactionist approach, rather than in isolation.
Dopamine hypothesis
There is strong supporting evidence.
- Davies et al 1989, did a meta analysis of over 100 studies.
- He found that 70% of those who were on antipsychotics improved compared to the 25%
that were on placebos.
- This means that antipsychotics block dopamine receptors.
- Therefore, suggesting that the dopamine hypothesis is an accurate explanation.
However, the interactionist position that biology and the environment play equal roles in
developing schizophrenia is a better approach.
- tienari et al 2004
- 19,000 Finnish children with biological mothers who had schizophrenia
- those place in adoptive homes, with childbearing styles, characterised by criticism were
more likely to develop schizophrenia (double bind theory)
- Furthermore, these children did not have a genetic risk factor, nor a same pattern within
them.
- The adopted children placed in highly critical homes, but did not have a biological mother
with schizophrenia did not have an increased risk of developing it.
- This strengthens the idea that a genetic exclamation assistant schizophrenia is most
convincing, only when used as part of the interactionist approach, rather than in isolation.
schizophrenia.
AO1 two types of classification systems:
- diagnostic and statistical manual (DSM) specific diagnostic criteria and a minimum of
two out of five key features for at least one month.
- Internal classification of disease (ICD), broader approach, stating that the clinical
picture is dominated by relatively stable, often paranoid delusions
To have a consistently accurate diagnosis, the systems must be valid and reliable
- validity is accuracy.
- Reliability is consistency.
Comorbidity is when an individual has the tendency of having more than one disorder at the
same time. For Example, an individual with schizophrenia may also develop depression at the
same time, and this increases the chance of misdiagnosis, undermining, validity and reliability.
Symptom overlap is when different disorder symptoms are shared and this leads to
misdiagnosis. For example, someone with schizophrenia might share symptoms of depression,
for example, avolition.
AO3 supporting research for comorbidity
- research found that 47% of patients diagnosed with schizophrenia also have diagnosis of
substance abuse
- 29% having an additional diagnosis of PTSD
- The most significant comorbidity rate of 50% was found with depression, running
alongside schizophrenia.
- Therefore, this suggests that these disorders may not be different disorders and we should
instead diagnose them as one disorder.
- This leads to the conclusion that the DSM and ICD are flawed.
Culture bias
- The average population of schizophrenics is 1%
- African Americans are nine times more likely to be diagnosed with schizophrenia in the uk
- However when research was conducted in Jamaica and Trinidad, it was found there’s only
a 1% likelihood therefore eliminating the idea of it being genetic in Afro Americans
Supporting research, suggests that validity and reliability are quite strong
- hollis in 2000 found a good correlation between symptoms of patients with schizophrenia
and the DSM criteria
- Jakobsen et al (2005) found a 98% inter-rater reliability amongst clinicians using the ICD’s
re-worked criteria, which appears to show that different doctors do reach highly similar
conclusions when drawing on the classification systems to diagnose the same patients.
- This suggests that the diagnosis is valid as the DSM enables doctors to diagnose people
However, research suggests the opposite.
- Study ‘on being sane in insane places’ 1973
- 2 Psychiatrists diagnosed the same patients using the DSM.
- Found that one diagnose 26 patience was having schizophrenia, whereas the other only
diagnose 13
- Suggest that interrater reliability is poor as their judgements were subjective and not
based on an objective and accurate criteria.
Discuss the biological explanation of schizophrenia
AO1 Genetics
- Inherited in DNA which runs in the family.
- The more similar the DNA the higher concordance rate
, - Therefore, there is a genetic predisposition, which is polygenic.
- 108 different genes seen in those with schizophrenia that both have many potential
genetic roots.
- Helps account for range of symptoms
Dopamine hypothesis
- initial theory: hyperdopaminergia
- Excesses receptors = increased activity
- Pos Symptoms include auditory hallucinations, which are caused from the
increased uptake in Broca’s area
- Later theory: hypodopaminergia
- Lowered dopamine activity
- The prefrontal cortex impacts thinking and decision-making, and this could lead to
avolition and the flat effect (neg)
Davies et al - concluded that it could be both of these theories as dopamine overall cause the
symptoms
AO3 genetics
research support of twin studies
- Found that the concordance rate is significantly higher for MZ twins compared to DZ twins.
- Kallman:
- Monozygotic twins - concordance rate up to 86%
- Dizygotic twins - concordance rate of only 15%
- This supports the idea that the more similar the DNA the higher the concordance rate.
- therefore suggest that predisposition is a key factor.
However, the interactionist position that biology and the environment play equal roles in
developing schizophrenia is a better approach.
- tienari et al 2004
- 19,000 Finnish children with biological mothers who had schizophrenia
- those place in adoptive homes, with childbearing styles, characterised by criticism were
more likely to develop schizophrenia (double bind theory)
- Furthermore, these children did not have a genetic risk factor, nor a pattern within them.
- The adopted children placed in highly critical homes, but did not have a biological mother
with schizophrenia did not have an increased risk of developing it.
- This strengthens the idea that a genetic exclamation assistant schizophrenia is most
convincing, only when used as part of the interactionist approach, rather than in isolation.
Dopamine hypothesis
There is strong supporting evidence.
- Davies et al 1989, did a meta analysis of over 100 studies.
- He found that 70% of those who were on antipsychotics improved compared to the 25%
that were on placebos.
- This means that antipsychotics block dopamine receptors.
- Therefore, suggesting that the dopamine hypothesis is an accurate explanation.
However, the interactionist position that biology and the environment play equal roles in
developing schizophrenia is a better approach.
- tienari et al 2004
- 19,000 Finnish children with biological mothers who had schizophrenia
- those place in adoptive homes, with childbearing styles, characterised by criticism were
more likely to develop schizophrenia (double bind theory)
- Furthermore, these children did not have a genetic risk factor, nor a same pattern within
them.
- The adopted children placed in highly critical homes, but did not have a biological mother
with schizophrenia did not have an increased risk of developing it.
- This strengthens the idea that a genetic exclamation assistant schizophrenia is most
convincing, only when used as part of the interactionist approach, rather than in isolation.
