Schizophrenia
Classification of schizophrenia
The nature of schizophrenia
● Schizophrenia = a type of psychosis characterised by a profound disruption of cognition and
emotion & a loss of contact with external reality
● Affects about 1% of population at some point in their lifetime - many continue to lead normal lives
after diagnosis and treatment
● Most often diagnosed between 15 and 35 & men and women affected equally
Diagnosing schizophrenia
● Use a diagnostic manual - e.g. DSM-V
● The symptoms are typically divided into positive and negative symptoms
● Positive symptoms = those that appear to reflect an excess or distortion of normal functions
● Negative symptoms = those that appear to reflect a reduction or loss of normal functions
Positive symptoms
Hallucinations:
● Bizarre, unreal perceptions of the environment that are usually auditory (hearing voices others
cant)
● May also be visual (seeing things others can't, e.g. lights, faces or objects) olfactory (smelling
things that others cant) or tactile (e.g. feelings bugs are crawling on you or something touching
the skin)
● Many schizophrenics report hearing a voice or several telling them to do something or
commenting on their behaviour
Delusions:
● Firmly held erroneous beliefs that are caused by distortions of reasoning or misinterpretations of
perceptions or experiences
● Bizarre beliefs that seem real to the person but are not actually real
● Delusions can be paranoid - e.g. believe they are being followed, that there are hidden cameras
in their house
● Can also involve inflated beliefs about a person's power / importance - e.g. may believe they are
famous or have special powers
● Delusions of reference - when events in environment appear to be directly related to them, e.g.
special personal messages being communicated through TV
Disorganised speech:
● The result of abnormal thought processes where individual has problems organising their
thoughts and this shows up in their speech
● E.g. may slip from one topic to another
Grossly disorganised or catatonic behaviour:
, ● The inability or motivation to initiate a task or to complete it once its started, leading to difficulties
in daily life
● Characterised by a reduction to immediate environment, rigid postures or aimless motor activity
● E.g. dress in bizarre ways, like wearing lots of clothes on a hot summer day
Negative symptoms
● Makinen et al found that about 1 in 3 schizophrenia patients suffer from negative symptoms
● -ve symptoms weaken the person's ability to cope with everyday activities, affecting their quality
of life and ability to manage without significant help
● They are typically unaware of the extent of their -ve symptoms
● Enduring -ve symptoms is sometimes referred to as ‘deficit syndrome’ which is characterised by
the presence of at least 2 -ve symptoms for 12+ months
● Those with deficit syndrome have been found to have more pronounces cognitive deficits and
poorer outcomes than those who don't have this syndrome
● Milev et al reported worse functioning outcomes in those with more prominent -ve symptoms
● -ve symptoms respond poorly to antipsychotic treatment
Speech poverty:
● The lessening of speech fluency and productivity which reflects slowing or blocked thoughts
● Those who display speech poverty display a number of characteristic signs - e.g. may produce
fewer words in a given time on a task of verbal fluency as have more difficulty in spontaneously
producing them
Avolition:
● The reduction, difficulty or inability to initiate and persist in goal directed behaviour - e.g. sitting in
the house for hours not doing anything
● Often mistaken for disinterest
Affective flattening:
● Reduction in the range and intensity of emotional expression, including facial expression, voice
tone, eye contact and body language
● Compared to controls without this symptom they show fewer body and facial movements and
smiles and less co-verbal behaviour (movements of hand, head and face that usually accompany
speech)
● May also show a deficit in prosody (paralinguistic features like tempo, loudness and pausing
which provide extra info and gives cues to listener as to emotional or attitudinal content and turn
taking)
Anhedonia:
● A loss of interest or pleasure in all or almost all activities or a lack of reactivity to normally
pleasurable stimuli
● May be pervasive or confined to a certain aspect of experience
● Physical anhedonia - inability to experience physical pleasures, such as from food or bodily
contact
● Social anhedonia - inability to experience pleasure from interpersonal situations, like interacting
with others
Reliability and validity in diagnosis and classification
, Reliability
● Reliability = consistency of measurements - would expect any measurements to produce the
same data if taken on successive occasions
● The diagnosis of schizophrenia should be repeatable - clinicians must reach same conclusions at
2 different points in time (test retest reliability) or for clinicians to reach the same conclusions
(inter-rater reliability)
● Inter-rater reliability measured by a kappa score - 1 = perfect inter-rater agreement & 0 = no
agreement, score above 0.7 is generally good (i.e. expect clinicians to get the diagnosis right
70% of the time)
● In the DSM-V field trials Regier et al found the diagnosis of schizophrenia had a kappa score of
only 0.46
Cultural differences in diagnosis:
● Research suggests that significant variation between countries when diagnosing schizophrenia
- Copeland (1971) gave 134 US and 194 British psychiatrists a description of a patients
with schizophrenia
- 69% of the US psychiatrists diagnosed schizophrenia but only 2% of the British ones did
● One of the main characteristics, hearing voices, appears to be influenced by cultural environment
- Luuhrmann et al interviewed 60 adults diagnosed with schizophrenia
- 20 each in Ghana, India and US
- Each asked about voices heard
- Many of African and Indian participants said voices were playful and offered advice but
the US ones said the voices were hateful and violent
Validity
● The diagnosis should be real and distinct from other disorders (external validity)
● Does it measure what it claims to measure (internal validity)
Gender bias in diagnosis:
● Accuracy of diagnosis is dependant on the gender of an individual
● Due to a number of reasons
- E.g. gender bias diagnostic criteria or clinicians basing judgements on stereotypical
beliefs held about gender - critics of the DSM diagnostic criteria argue that some
diagnostic categories are biassed towards pathologizing one gender
- Broverman et al (1970) found clinicians in the US equated mentally healthy ‘adult’
behaviour to mentally healthy ‘male’ behaviour, so women perceived as less mentally
healthy
Symptom overlap:
● Overlap of symptoms in different disorders leading a psychiatrist to a wrong diagnosis - symptom
found in one disorder also found in another
● E.g. many schizophrenia symptoms also symptoms of depression
● Ellason and Ross (1995) pointed out that those with DID have more schizophrenic symptoms
than people being diagnosed with schizophrenia
● Read (2004) found most who are diagnosed with schizophrenia have sufficient symptoms of other
disorders that they could also receive at least one other diagnosis
Comorbidity:
● Refers to the extent that two or more conditions occur at the same time in patients - e.g.
schizophrenia and depression
Classification of schizophrenia
The nature of schizophrenia
● Schizophrenia = a type of psychosis characterised by a profound disruption of cognition and
emotion & a loss of contact with external reality
● Affects about 1% of population at some point in their lifetime - many continue to lead normal lives
after diagnosis and treatment
● Most often diagnosed between 15 and 35 & men and women affected equally
Diagnosing schizophrenia
● Use a diagnostic manual - e.g. DSM-V
● The symptoms are typically divided into positive and negative symptoms
● Positive symptoms = those that appear to reflect an excess or distortion of normal functions
● Negative symptoms = those that appear to reflect a reduction or loss of normal functions
Positive symptoms
Hallucinations:
● Bizarre, unreal perceptions of the environment that are usually auditory (hearing voices others
cant)
● May also be visual (seeing things others can't, e.g. lights, faces or objects) olfactory (smelling
things that others cant) or tactile (e.g. feelings bugs are crawling on you or something touching
the skin)
● Many schizophrenics report hearing a voice or several telling them to do something or
commenting on their behaviour
Delusions:
● Firmly held erroneous beliefs that are caused by distortions of reasoning or misinterpretations of
perceptions or experiences
● Bizarre beliefs that seem real to the person but are not actually real
● Delusions can be paranoid - e.g. believe they are being followed, that there are hidden cameras
in their house
● Can also involve inflated beliefs about a person's power / importance - e.g. may believe they are
famous or have special powers
● Delusions of reference - when events in environment appear to be directly related to them, e.g.
special personal messages being communicated through TV
Disorganised speech:
● The result of abnormal thought processes where individual has problems organising their
thoughts and this shows up in their speech
● E.g. may slip from one topic to another
Grossly disorganised or catatonic behaviour:
, ● The inability or motivation to initiate a task or to complete it once its started, leading to difficulties
in daily life
● Characterised by a reduction to immediate environment, rigid postures or aimless motor activity
● E.g. dress in bizarre ways, like wearing lots of clothes on a hot summer day
Negative symptoms
● Makinen et al found that about 1 in 3 schizophrenia patients suffer from negative symptoms
● -ve symptoms weaken the person's ability to cope with everyday activities, affecting their quality
of life and ability to manage without significant help
● They are typically unaware of the extent of their -ve symptoms
● Enduring -ve symptoms is sometimes referred to as ‘deficit syndrome’ which is characterised by
the presence of at least 2 -ve symptoms for 12+ months
● Those with deficit syndrome have been found to have more pronounces cognitive deficits and
poorer outcomes than those who don't have this syndrome
● Milev et al reported worse functioning outcomes in those with more prominent -ve symptoms
● -ve symptoms respond poorly to antipsychotic treatment
Speech poverty:
● The lessening of speech fluency and productivity which reflects slowing or blocked thoughts
● Those who display speech poverty display a number of characteristic signs - e.g. may produce
fewer words in a given time on a task of verbal fluency as have more difficulty in spontaneously
producing them
Avolition:
● The reduction, difficulty or inability to initiate and persist in goal directed behaviour - e.g. sitting in
the house for hours not doing anything
● Often mistaken for disinterest
Affective flattening:
● Reduction in the range and intensity of emotional expression, including facial expression, voice
tone, eye contact and body language
● Compared to controls without this symptom they show fewer body and facial movements and
smiles and less co-verbal behaviour (movements of hand, head and face that usually accompany
speech)
● May also show a deficit in prosody (paralinguistic features like tempo, loudness and pausing
which provide extra info and gives cues to listener as to emotional or attitudinal content and turn
taking)
Anhedonia:
● A loss of interest or pleasure in all or almost all activities or a lack of reactivity to normally
pleasurable stimuli
● May be pervasive or confined to a certain aspect of experience
● Physical anhedonia - inability to experience physical pleasures, such as from food or bodily
contact
● Social anhedonia - inability to experience pleasure from interpersonal situations, like interacting
with others
Reliability and validity in diagnosis and classification
, Reliability
● Reliability = consistency of measurements - would expect any measurements to produce the
same data if taken on successive occasions
● The diagnosis of schizophrenia should be repeatable - clinicians must reach same conclusions at
2 different points in time (test retest reliability) or for clinicians to reach the same conclusions
(inter-rater reliability)
● Inter-rater reliability measured by a kappa score - 1 = perfect inter-rater agreement & 0 = no
agreement, score above 0.7 is generally good (i.e. expect clinicians to get the diagnosis right
70% of the time)
● In the DSM-V field trials Regier et al found the diagnosis of schizophrenia had a kappa score of
only 0.46
Cultural differences in diagnosis:
● Research suggests that significant variation between countries when diagnosing schizophrenia
- Copeland (1971) gave 134 US and 194 British psychiatrists a description of a patients
with schizophrenia
- 69% of the US psychiatrists diagnosed schizophrenia but only 2% of the British ones did
● One of the main characteristics, hearing voices, appears to be influenced by cultural environment
- Luuhrmann et al interviewed 60 adults diagnosed with schizophrenia
- 20 each in Ghana, India and US
- Each asked about voices heard
- Many of African and Indian participants said voices were playful and offered advice but
the US ones said the voices were hateful and violent
Validity
● The diagnosis should be real and distinct from other disorders (external validity)
● Does it measure what it claims to measure (internal validity)
Gender bias in diagnosis:
● Accuracy of diagnosis is dependant on the gender of an individual
● Due to a number of reasons
- E.g. gender bias diagnostic criteria or clinicians basing judgements on stereotypical
beliefs held about gender - critics of the DSM diagnostic criteria argue that some
diagnostic categories are biassed towards pathologizing one gender
- Broverman et al (1970) found clinicians in the US equated mentally healthy ‘adult’
behaviour to mentally healthy ‘male’ behaviour, so women perceived as less mentally
healthy
Symptom overlap:
● Overlap of symptoms in different disorders leading a psychiatrist to a wrong diagnosis - symptom
found in one disorder also found in another
● E.g. many schizophrenia symptoms also symptoms of depression
● Ellason and Ross (1995) pointed out that those with DID have more schizophrenic symptoms
than people being diagnosed with schizophrenia
● Read (2004) found most who are diagnosed with schizophrenia have sufficient symptoms of other
disorders that they could also receive at least one other diagnosis
Comorbidity:
● Refers to the extent that two or more conditions occur at the same time in patients - e.g.
schizophrenia and depression
