Discuss reliability and validity in the diagnosis and classification of schizophrenia.
Classification Positive Symptoms Negative Symptoms Issues in Diagnosis
● Schizo is seemingly ● Hallucinations: sensory experiences ● Neg symptoms: loss of normal ● Reliability: extent to which
unrelated symptoms. no basis in reality, distorted functioning usual abilities & diagnosis of schizo is consistent
● Many misconceptions. perception of real things. Voices experiences. ● Validity: extent to which
● DSM: 1 positive symptom, ● Usually auditory, visual, tactile. ● Avolition: loss of motivation for diagnosis + classification
eg delusions. ● Delusions: behave in way bizarre to everyday tasks, eg personal care measures what they designed to
● ICD: 2+ negative others, eg believing in conspiracy ● Unwillingness to carry out goal- measure, eg measure schizo.
symptoms for diagnosis, ● Excess or distortion of normal directed behaviours ● Co-morbidity: 2 illnesses
eg avolition/speech functioning. Paranoia ● Speech poverty: reduction in occurring together, confuses
poverty. ● Negative symptoms: anhedonia, amount/quality, delay in verbal diagnosis + treatment
● Positive: excess of inability to feel pleasure, pleasurable responses during conversation ● Symptom overlap: 2+ conditions
normal functioning activities. Echolalia, catalonia ● DSM emphasises incoherence share symptoms, question validity
Low reliability, Cheniaux Buckley, co-morbidity Rosenhan, pseudopatients Gender Bias
● 2 psychiatrists ● 2 or more conditions occur together ● Sane observers went into ● Longenecker looked at studies of
independently diagnose ● Questions whether they are actually a hospital saying they had prevalence of schizo, found since
100 patients w DSM, ICD single condition hallucinations of word ‘thud, 1980s, men more diagnosed
● Inter-rater reliability low ● Buckley found half of patients w hollow’. Then normal than women.
1 diagnosed 26 w schizo + schizo also had depression, 47% ● 11 pseudos diagnosed w schizo, ● Cotton found ♀ patients function
44 with ICD had substance abuse average hospital stay = 19 days better than men, have better
● 2nd psychiatrist diagnosed ● In terms of classification, if severe ● Staff couldn’t distinguish sanity + interpersonal functioning, bias
13 w DSM, 24 w ICD depression looks like schizo, may be insanity, no validity, unethical practitioners to under diagnose
● Inconsistency between because they are single condition, ● Repeated w schizos, 41/193 were schizo. Men & women w same
professionals limiting. which is confusing. deemed pseudopatients symptoms have diff diagnoses.
Cheniaux, Low validity Real World Application Culture Bias Biological Approach
● Assess criterion validity, ● Psychiatrists cannot reliably tell the ● African americans more likely to ● Using the DSM and ICD in
do diff assessments lead difference between an insane and be diagnosed w schizo in UK, diagnosis is scientific, requires
to same diagnosis sane person, calling into question the rates in West Indies not as high, monitoring positive and negative
● He found schizo more reliability of a schizophrenia so not due to genetic symptoms
likely diagnosed w ICD vs diagnosis. Consequences of co-morb vulnerability. ● Detection of co-morbidity, argued
DSM, ergo poor validity ● ‘Normal’ behaviour was ● Higher rates bc behaviour it is unscientific due to limitation of
● Schizo either misinterpreted as ‘abnormal’ to classed as positive symptoms eg separating illnesses.
overdiagnosed in ICD or support their idea that the delusions are normal in Africa,
underdiagnosed in DSM pseudopatients had a mental illness. eg hearing ancestors voices.
Describe and evaluate two or more biological explanations for schizophrenia.
Classification Positive Symptoms Negative Symptoms Issues in Diagnosis
● Schizo is seemingly ● Hallucinations: sensory experiences ● Neg symptoms: loss of normal ● Reliability: extent to which
unrelated symptoms. no basis in reality, distorted functioning usual abilities & diagnosis of schizo is consistent
● Many misconceptions. perception of real things. Voices experiences. ● Validity: extent to which
● DSM: 1 positive symptom, ● Usually auditory, visual, tactile. ● Avolition: loss of motivation for diagnosis + classification
eg delusions. ● Delusions: behave in way bizarre to everyday tasks, eg personal care measures what they designed to
● ICD: 2+ negative others, eg believing in conspiracy ● Unwillingness to carry out goal- measure, eg measure schizo.
symptoms for diagnosis, ● Excess or distortion of normal directed behaviours ● Co-morbidity: 2 illnesses
eg avolition/speech functioning. Paranoia ● Speech poverty: reduction in occurring together, confuses
poverty. ● Negative symptoms: anhedonia, amount/quality, delay in verbal diagnosis + treatment
● Positive: excess of inability to feel pleasure, pleasurable responses during conversation ● Symptom overlap: 2+ conditions
normal functioning activities. Echolalia, catalonia ● DSM emphasises incoherence share symptoms, question validity
Low reliability, Cheniaux Buckley, co-morbidity Rosenhan, pseudopatients Gender Bias
● 2 psychiatrists ● 2 or more conditions occur together ● Sane observers went into ● Longenecker looked at studies of
independently diagnose ● Questions whether they are actually a hospital saying they had prevalence of schizo, found since
100 patients w DSM, ICD single condition hallucinations of word ‘thud, 1980s, men more diagnosed
● Inter-rater reliability low ● Buckley found half of patients w hollow’. Then normal than women.
1 diagnosed 26 w schizo + schizo also had depression, 47% ● 11 pseudos diagnosed w schizo, ● Cotton found ♀ patients function
44 with ICD had substance abuse average hospital stay = 19 days better than men, have better
● 2nd psychiatrist diagnosed ● In terms of classification, if severe ● Staff couldn’t distinguish sanity + interpersonal functioning, bias
13 w DSM, 24 w ICD depression looks like schizo, may be insanity, no validity, unethical practitioners to under diagnose
● Inconsistency between because they are single condition, ● Repeated w schizos, 41/193 were schizo. Men & women w same
professionals limiting. which is confusing. deemed pseudopatients symptoms have diff diagnoses.
Cheniaux, Low validity Real World Application Culture Bias Biological Approach
● Assess criterion validity, ● Psychiatrists cannot reliably tell the ● African americans more likely to ● Using the DSM and ICD in
do diff assessments lead difference between an insane and be diagnosed w schizo in UK, diagnosis is scientific, requires
to same diagnosis sane person, calling into question the rates in West Indies not as high, monitoring positive and negative
● He found schizo more reliability of a schizophrenia so not due to genetic symptoms
likely diagnosed w ICD vs diagnosis. Consequences of co-morb vulnerability. ● Detection of co-morbidity, argued
DSM, ergo poor validity ● ‘Normal’ behaviour was ● Higher rates bc behaviour it is unscientific due to limitation of
● Schizo either misinterpreted as ‘abnormal’ to classed as positive symptoms eg separating illnesses.
overdiagnosed in ICD or support their idea that the delusions are normal in Africa,
underdiagnosed in DSM pseudopatients had a mental illness. eg hearing ancestors voices.
Describe and evaluate two or more biological explanations for schizophrenia.
