Schizophrenia
Schizophrenia= A severe mental disorder where contact with reality and insight are
impaired- example of psychosis
Diagnosis and Classification:
● World Health Organisation’s International Classification of Disease (ICD-10) - Two
or more negative symptoms= diagnosis of schizophrenia
● American Psychiatric Association’s Diagnostic and Statistical Manual (DSM-5) -
One positive symptom= diagnosis of schizophrenia
Positive Symptoms= Additional experiences beyond those of ordinary existence
● Hallucinations- Unusual Sensory experiences. Some are in relation to things
happening in the environment, whereas others aren’t. Includes hearing voices,
seeing distorted facial expressions or people/animals that aren’t there
● Delusions- Irrational beliefs. Common delusions include being important
historical/political/religious figures, being persecuted, having super powers or
believing that the body is under external control
Negative Symptoms= Involve the loss of usual abilities and experiences
● Speech Poverty- Reduction in the amount and quality of speech, emphasis on
speech disorganisation (Positive Symptom in DSM-5) - speech becomes
incoherent/speaker changes topic mid-sentence
● Avolition- Finding it difficult to begin or keep up with goal directed activity. Sharply
reduced motivation to carry out a range of activities. Nancy Andreason (1982) - 3
Stages of avolition:
1. Poor Hygiene and Grooming
2. Lack of Persistence in Work/Education
3. Lack of Energy
Evaluations:
1. Good Reliability:
● Psychiatric Diagnosis is said to be reliable when different diagnosing clinicians reach
the same diagnosis for the same individual (inter-rater reliability) and when the same
clinician reaches the same diagnosis for the same individual on 2 occasions
(test-retest reliability)
● Flavia Osorio et al (2019) reported excellent reliability for diagnosis of schizophrenia
in 180 people using DSM-5
● Inter-rater reliability- .97 and test-retest- .92
, 2. Low Validity:
● One way to assess validity of a psychiatric diagnosis is criterion validity
● Ellie Cheniaux et al (2009) had 2 psychiatrists independently assess the same 100
clients using ICD-10 and DSM-5 criteria and found that 68 were diagnosed with
schizophrenia under ICD and 39 under DSM
● This suggests schizophrenia is either under or over diagnosed
● However, in the Osorio et al Study, there was excellent agreement between clinicians
when they used 2 measures to diagnose schizophrenia, both derived from DSM-5
● Suggests that criterion validity for diagnosing schizophrenia is good, provided it takes
place within a single diagnostic system
3. Comorbidity:
● If conditions occur together, this questions the validity of diagnosis and classification-
might actually be a single condition
● Schizophrenia is commonly diagnosed with other conditions- e.g. Buckley et al
found that 50% of individuals with a diagnosis of schizophrenia also have depression,
47% have a comorbidity with substance abuse and 23% with OCD
● This is a problem for classification because it means schizophrenia may not exist as
a distinct condition, and is a problem for diagnosis as at least some people with
schizophrenia may have unusual cases of conditions such as depression
4. Gender Bias in Diagnosis:
● Since 1980s, men have been diagnosed with schizophrenia more commonly than
women (1.4:1- Fischer and Buchanan 2017)
● A possible explanation is that women are less vulnerable than men, perhaps due to
genetic factors
● However, it seems more likely that women are underdiagnosed because they have
closer relationships and hence get support (Cotton et al 2009)
● This leads to women with schizophrenia often functioning better than men
● Underdiagnosis is a gender bias and means that women may not be receiving
treatment and services that benefit them
5. Culture Bias in Diagnosis:
● Some symptoms of schizophrenia (e.g. hearing voices) have different meanings in
different cultures
● E.g. in Haiti, some people believe that voices are communications from ancestors
● British people of African-Caribbean descent are up to 9 times more likely to receive a
diagnosis than White British people (Pinto and Jones 2008)
● The most likely explanation for this is culture bias in diagnosis of clients by
psychiatrists from a different cultural background
● This appears to lead to an overinterpretation of symptoms in Black British people
(Escobar 2012)
● This means that British African Caribbean people may be discriminated against by a
culturally biased diagnostic system
6. Symptom Overlap:
Schizophrenia= A severe mental disorder where contact with reality and insight are
impaired- example of psychosis
Diagnosis and Classification:
● World Health Organisation’s International Classification of Disease (ICD-10) - Two
or more negative symptoms= diagnosis of schizophrenia
● American Psychiatric Association’s Diagnostic and Statistical Manual (DSM-5) -
One positive symptom= diagnosis of schizophrenia
Positive Symptoms= Additional experiences beyond those of ordinary existence
● Hallucinations- Unusual Sensory experiences. Some are in relation to things
happening in the environment, whereas others aren’t. Includes hearing voices,
seeing distorted facial expressions or people/animals that aren’t there
● Delusions- Irrational beliefs. Common delusions include being important
historical/political/religious figures, being persecuted, having super powers or
believing that the body is under external control
Negative Symptoms= Involve the loss of usual abilities and experiences
● Speech Poverty- Reduction in the amount and quality of speech, emphasis on
speech disorganisation (Positive Symptom in DSM-5) - speech becomes
incoherent/speaker changes topic mid-sentence
● Avolition- Finding it difficult to begin or keep up with goal directed activity. Sharply
reduced motivation to carry out a range of activities. Nancy Andreason (1982) - 3
Stages of avolition:
1. Poor Hygiene and Grooming
2. Lack of Persistence in Work/Education
3. Lack of Energy
Evaluations:
1. Good Reliability:
● Psychiatric Diagnosis is said to be reliable when different diagnosing clinicians reach
the same diagnosis for the same individual (inter-rater reliability) and when the same
clinician reaches the same diagnosis for the same individual on 2 occasions
(test-retest reliability)
● Flavia Osorio et al (2019) reported excellent reliability for diagnosis of schizophrenia
in 180 people using DSM-5
● Inter-rater reliability- .97 and test-retest- .92
, 2. Low Validity:
● One way to assess validity of a psychiatric diagnosis is criterion validity
● Ellie Cheniaux et al (2009) had 2 psychiatrists independently assess the same 100
clients using ICD-10 and DSM-5 criteria and found that 68 were diagnosed with
schizophrenia under ICD and 39 under DSM
● This suggests schizophrenia is either under or over diagnosed
● However, in the Osorio et al Study, there was excellent agreement between clinicians
when they used 2 measures to diagnose schizophrenia, both derived from DSM-5
● Suggests that criterion validity for diagnosing schizophrenia is good, provided it takes
place within a single diagnostic system
3. Comorbidity:
● If conditions occur together, this questions the validity of diagnosis and classification-
might actually be a single condition
● Schizophrenia is commonly diagnosed with other conditions- e.g. Buckley et al
found that 50% of individuals with a diagnosis of schizophrenia also have depression,
47% have a comorbidity with substance abuse and 23% with OCD
● This is a problem for classification because it means schizophrenia may not exist as
a distinct condition, and is a problem for diagnosis as at least some people with
schizophrenia may have unusual cases of conditions such as depression
4. Gender Bias in Diagnosis:
● Since 1980s, men have been diagnosed with schizophrenia more commonly than
women (1.4:1- Fischer and Buchanan 2017)
● A possible explanation is that women are less vulnerable than men, perhaps due to
genetic factors
● However, it seems more likely that women are underdiagnosed because they have
closer relationships and hence get support (Cotton et al 2009)
● This leads to women with schizophrenia often functioning better than men
● Underdiagnosis is a gender bias and means that women may not be receiving
treatment and services that benefit them
5. Culture Bias in Diagnosis:
● Some symptoms of schizophrenia (e.g. hearing voices) have different meanings in
different cultures
● E.g. in Haiti, some people believe that voices are communications from ancestors
● British people of African-Caribbean descent are up to 9 times more likely to receive a
diagnosis than White British people (Pinto and Jones 2008)
● The most likely explanation for this is culture bias in diagnosis of clients by
psychiatrists from a different cultural background
● This appears to lead to an overinterpretation of symptoms in Black British people
(Escobar 2012)
● This means that British African Caribbean people may be discriminated against by a
culturally biased diagnostic system
6. Symptom Overlap:
