RELIABILITY IN DIAGNOSIS & CLASSIFICATION
STRENGTHS : LIMITATIONS :
1. The DSM and ICD-10 is reliable 1. Lack of inter-rater reliability
- Different clinicians use the - Despite the increase in DSM 3, there has been little
same system (e.g.ICD evidence that DSM is routinely used with mental health
which is used world wide) clinicians.
so they should arrive at - Whaley found inter-rater reliability correlations in the
the same diagnosis for the diagnosis of sz as low as 0.11.
same individual. - Furthermore, Rosenhan conducted a study, being sane in
- DSM is highly reliable as it insane places, where ‘normal’ people presented themselves
looks at the length of to psychiatric hospitals in the US claiming they heard an
symptoms which are unfamiliar voice in their head.
present allowing the - It showed that psychiatrists cannot reliably tell the
psychiatrists to give an difference between an insane and sane person, calling
accurate diagnosis which into question the reliability of a Sz diagnosis .
remains consistent - Also, ‘normal’ behaviour was misinterpreted as ‘abnormal’
between different to support their idea that pseudopatients had mental
psychiatrists. illness THEREFORE this suggests the validity of psychiatric
- Also the DSM is constantly diagnoses was low & the DSM was flawed.
changing to improve their 2. Cultural differences in diagnosis
reliability. - Research conducted by Cooper et. al suggests that When
shown the same video clips, New York psychiatrists are
twice as likely to diagnose schizophrenia than London
psychiatrists.
- London psychiatrists were twice as likely to diagnose
mania or depression than New York psychiatrists.
- Therefore this suggests there is a low consistency rate in
the diagnosis of psychiatric disorders.
3. Lack of Test-retest reliability
- This is when the same patient will receive the same
diagnosis if assessed more than once by the same
psychiatrist. Mary Seeman found that initial diagnosis of
schizophrenia, especially in women, is more susceptible to
change as clinicians found out more and more about their
patients.
- This clearly shows the unreliability of diagnosing patients.
VALIDITY IN DIAGNOSIS & CLASSIFICATION
STRENGTHS : LIMITATIONS :
1. Research supports gender bias in diagnosis
- It appears that female patients typically function better
than men, being more likely to work & have good family
relationships (Cotton et al 2009)
- This could therefore explain why some women haven’t
been diagnosed with Sz whereas men with similar
symptoms might have been; their functioning may bias
psychiatrists to under-diagnose Sz
- This therefore lowers the validity of the diagnosis of Sz
2. Cultural bias in diagnosis
- African Americans & English ppl of Afro-Caribbean
background are several times more likely to be diagnosed
with Sz than white ppl
- This could be because positive symptoms e.g. hearing
voices may be seen as more acceptable in African
cultures due to cultural beliefs OR due to racial
discrimintation in diagnosis
- Jacob Escobar noted that overwhelmingly white
psychiatrists tend to over-interpret symptoms & distrust
honesty of black ppl during diagnosis
- THEREFORE this lowers the validity of the diagnosis of Sz
3. Buckley provides evidence to support co-morbidity
- 50% Sz patients also have depression
- 47% have substance abuse
- 29% have PTSD
- 23% have OCD
- This lowers the validity of the diagnosis of Sz
BIOLOGICAL EXPLANATIONS FOR SCHIZOPHRENIA : GENETIC
STRENGTHS : LIMITATIONS :
1. There are multiple sources of 1. Evidence suggests that Sz is not only caused by genetics
evidence for the genetic - This is because no study has found a 100% concordance
susceptibility of Sz rate between MZ twins SO Sz can’t only be caused by
- FOR EXAMPLE, Gottesman genes
, 1991 large-scale family - Also, a shared environment may be the cause of higher
study, Tierani 2004 concordance rates in family studies (e.g. Gottesman)
adoption studies because children imitate Sz behaviours
- THEREFORE there is - ALSO, Joseph 2004 suggested that it is widely accepted
overwhelming evidence to that MZ twins are treated more similarly, encounter more
suggest that genetic similar enviro & experience more ‘identity confusion’ e.g.
factors make some ppl being treated as ‘the twins’ rather than indvs SO
more vulnerable to concordance rates may only reflect enviro factors
developing Sz than others - THEREFORE this means that other factors need to be
& whilst this research considered e.g. psychological factors
doesn’t suggest that Sz is - COULD EXPAND THIS POINT USING A PSYCHOLOGICAL
entirely genetic it does EXPLANATION !!!
suggest that genetic 1. Biologically reductionist
susceptibility is very impo - The Genome Project has increased understanding of the
complexity of the gene.
- Given that a much lower number of genes exist than
anticipated, it is now recognised that genes have multiple
functions and that many genes behave.
- Schizophrenia is a multifactorial trait as it is the result of
multiple genes and environmental factors. This suggests
that the research into gene mapping is over simplistic as
schizophrenia is not due to a single gene.
- A better explanation could be epigenetics which explains
that it is not enough for a gene to be present it needs to
be switched on or off by environmental factors to become
active and lead to the development of characteristics such
as Sz.
BIOLOGICAL EXPLANATIONS FOR SCHIZOPHRENIA : NEURAL
STRENGTHS : LIMITATIONS :
1. Evidence for treatment 1. Opposing the dopamine hypothesis
- Leuct carried out a meta-analysis of 212 - Noll (2009) found that antipsychotics don’t
studies that had analysed the alleviate hallucinations and delusions in ⅓
effectiveness of different antipsychotic of people experiencing these symptoms.
drugs compared to a placebo. - He found people with normal dopamine
- He found that all drugs were significantly levels still experience hallucinations
more effective than a placebo in the therefore blocking the dopamine 2
treatment of + and - symptoms . receptors of these individuals have little or
2. There is evidence to support the dopamine no effect on their symptoms.
hypothesis - This suggests other neurotransmitter
- Dopamine agonists like amphetamines systems produce + symptoms associated
that increase levels of dopamine make Sz with Sz & that it is not solely dopamine
worse & can produce Sz-like symptoms in consequently disproving the dopamine
non-sufferers (Curran et al) hypothesis
- Antipsychotic drugs work by reducing
dopamine activity (Tauscher et al)
- THEREFORE both types of drugs & their
related studies highlight the impo role of
dopamine in Sz
- HOWEVER the use of drug arguments as
evidence for supporting the dopamine
hypothesis suffers from the aetiological
fallacy → this is because, for example,
antipsychotic drugs may reduce the
symptoms of Sz but it doesn’t mean that
the symptoms were due to an absence of
antipsychotic drugs THEREFORE cannot
establish a cause & effect relationship
PSYCHOLOGICAL EXPLANATIONS OF SZ : FAMILY DYSFUNCTION
STRENGTHS : LIMITATIONS :
1. Research supporting family relationships by Tienari et 1. Issues with methodology
al (1994) - Most studies are retrospective, which
- supports the importance of family is an issue because the data obtained
relationships in the development of may be unreliable due to errors in
schizophrenia recalling information from the past.
- They found that adopted children who had - Also many of the studies involve
schizophrenia biological parents were more families being observed which leads
likely to develop schizophrenia than those with to the hawthorne effect. The studies
non-schizophrenic biological parents conducted involve self report as well
- However this difference only emerged in which can lead to social desirability
situations where the adopted family was rated bias as individuals would want to be
as disturbed seen in a good light.
STRENGTHS : LIMITATIONS :
1. The DSM and ICD-10 is reliable 1. Lack of inter-rater reliability
- Different clinicians use the - Despite the increase in DSM 3, there has been little
same system (e.g.ICD evidence that DSM is routinely used with mental health
which is used world wide) clinicians.
so they should arrive at - Whaley found inter-rater reliability correlations in the
the same diagnosis for the diagnosis of sz as low as 0.11.
same individual. - Furthermore, Rosenhan conducted a study, being sane in
- DSM is highly reliable as it insane places, where ‘normal’ people presented themselves
looks at the length of to psychiatric hospitals in the US claiming they heard an
symptoms which are unfamiliar voice in their head.
present allowing the - It showed that psychiatrists cannot reliably tell the
psychiatrists to give an difference between an insane and sane person, calling
accurate diagnosis which into question the reliability of a Sz diagnosis .
remains consistent - Also, ‘normal’ behaviour was misinterpreted as ‘abnormal’
between different to support their idea that pseudopatients had mental
psychiatrists. illness THEREFORE this suggests the validity of psychiatric
- Also the DSM is constantly diagnoses was low & the DSM was flawed.
changing to improve their 2. Cultural differences in diagnosis
reliability. - Research conducted by Cooper et. al suggests that When
shown the same video clips, New York psychiatrists are
twice as likely to diagnose schizophrenia than London
psychiatrists.
- London psychiatrists were twice as likely to diagnose
mania or depression than New York psychiatrists.
- Therefore this suggests there is a low consistency rate in
the diagnosis of psychiatric disorders.
3. Lack of Test-retest reliability
- This is when the same patient will receive the same
diagnosis if assessed more than once by the same
psychiatrist. Mary Seeman found that initial diagnosis of
schizophrenia, especially in women, is more susceptible to
change as clinicians found out more and more about their
patients.
- This clearly shows the unreliability of diagnosing patients.
VALIDITY IN DIAGNOSIS & CLASSIFICATION
STRENGTHS : LIMITATIONS :
1. Research supports gender bias in diagnosis
- It appears that female patients typically function better
than men, being more likely to work & have good family
relationships (Cotton et al 2009)
- This could therefore explain why some women haven’t
been diagnosed with Sz whereas men with similar
symptoms might have been; their functioning may bias
psychiatrists to under-diagnose Sz
- This therefore lowers the validity of the diagnosis of Sz
2. Cultural bias in diagnosis
- African Americans & English ppl of Afro-Caribbean
background are several times more likely to be diagnosed
with Sz than white ppl
- This could be because positive symptoms e.g. hearing
voices may be seen as more acceptable in African
cultures due to cultural beliefs OR due to racial
discrimintation in diagnosis
- Jacob Escobar noted that overwhelmingly white
psychiatrists tend to over-interpret symptoms & distrust
honesty of black ppl during diagnosis
- THEREFORE this lowers the validity of the diagnosis of Sz
3. Buckley provides evidence to support co-morbidity
- 50% Sz patients also have depression
- 47% have substance abuse
- 29% have PTSD
- 23% have OCD
- This lowers the validity of the diagnosis of Sz
BIOLOGICAL EXPLANATIONS FOR SCHIZOPHRENIA : GENETIC
STRENGTHS : LIMITATIONS :
1. There are multiple sources of 1. Evidence suggests that Sz is not only caused by genetics
evidence for the genetic - This is because no study has found a 100% concordance
susceptibility of Sz rate between MZ twins SO Sz can’t only be caused by
- FOR EXAMPLE, Gottesman genes
, 1991 large-scale family - Also, a shared environment may be the cause of higher
study, Tierani 2004 concordance rates in family studies (e.g. Gottesman)
adoption studies because children imitate Sz behaviours
- THEREFORE there is - ALSO, Joseph 2004 suggested that it is widely accepted
overwhelming evidence to that MZ twins are treated more similarly, encounter more
suggest that genetic similar enviro & experience more ‘identity confusion’ e.g.
factors make some ppl being treated as ‘the twins’ rather than indvs SO
more vulnerable to concordance rates may only reflect enviro factors
developing Sz than others - THEREFORE this means that other factors need to be
& whilst this research considered e.g. psychological factors
doesn’t suggest that Sz is - COULD EXPAND THIS POINT USING A PSYCHOLOGICAL
entirely genetic it does EXPLANATION !!!
suggest that genetic 1. Biologically reductionist
susceptibility is very impo - The Genome Project has increased understanding of the
complexity of the gene.
- Given that a much lower number of genes exist than
anticipated, it is now recognised that genes have multiple
functions and that many genes behave.
- Schizophrenia is a multifactorial trait as it is the result of
multiple genes and environmental factors. This suggests
that the research into gene mapping is over simplistic as
schizophrenia is not due to a single gene.
- A better explanation could be epigenetics which explains
that it is not enough for a gene to be present it needs to
be switched on or off by environmental factors to become
active and lead to the development of characteristics such
as Sz.
BIOLOGICAL EXPLANATIONS FOR SCHIZOPHRENIA : NEURAL
STRENGTHS : LIMITATIONS :
1. Evidence for treatment 1. Opposing the dopamine hypothesis
- Leuct carried out a meta-analysis of 212 - Noll (2009) found that antipsychotics don’t
studies that had analysed the alleviate hallucinations and delusions in ⅓
effectiveness of different antipsychotic of people experiencing these symptoms.
drugs compared to a placebo. - He found people with normal dopamine
- He found that all drugs were significantly levels still experience hallucinations
more effective than a placebo in the therefore blocking the dopamine 2
treatment of + and - symptoms . receptors of these individuals have little or
2. There is evidence to support the dopamine no effect on their symptoms.
hypothesis - This suggests other neurotransmitter
- Dopamine agonists like amphetamines systems produce + symptoms associated
that increase levels of dopamine make Sz with Sz & that it is not solely dopamine
worse & can produce Sz-like symptoms in consequently disproving the dopamine
non-sufferers (Curran et al) hypothesis
- Antipsychotic drugs work by reducing
dopamine activity (Tauscher et al)
- THEREFORE both types of drugs & their
related studies highlight the impo role of
dopamine in Sz
- HOWEVER the use of drug arguments as
evidence for supporting the dopamine
hypothesis suffers from the aetiological
fallacy → this is because, for example,
antipsychotic drugs may reduce the
symptoms of Sz but it doesn’t mean that
the symptoms were due to an absence of
antipsychotic drugs THEREFORE cannot
establish a cause & effect relationship
PSYCHOLOGICAL EXPLANATIONS OF SZ : FAMILY DYSFUNCTION
STRENGTHS : LIMITATIONS :
1. Research supporting family relationships by Tienari et 1. Issues with methodology
al (1994) - Most studies are retrospective, which
- supports the importance of family is an issue because the data obtained
relationships in the development of may be unreliable due to errors in
schizophrenia recalling information from the past.
- They found that adopted children who had - Also many of the studies involve
schizophrenia biological parents were more families being observed which leads
likely to develop schizophrenia than those with to the hawthorne effect. The studies
non-schizophrenic biological parents conducted involve self report as well
- However this difference only emerged in which can lead to social desirability
situations where the adopted family was rated bias as individuals would want to be
as disturbed seen in a good light.
