Schizophrenia
Classification of schizophrenia
○ Schizophrenia i s a type of psychosis characterised by a p rofound d isruption o
f cognition and emotion.
○ It is a severe mental disorder where contact with e xternal reality is lost.
○ It affects about 1% of the population at some point in their lifetime.
○ Most often diagnosed between 15-35, w ith men and women equally affected.
○ Not every patient displays all the symptoms.
Diagnosing schizophrenia
○ Diathesis stress model i s a classification and description of over 200 mental disorders, grouped in terms of their
common features. ICD i s more commonly used in Europe.
○ Criterion A:
○ Two or more of the following symptoms for a significant portion of time during a 1 month period:
○ Delusions.
○ Hallucinations.
○ Disorgansised speech.
○ Grossly disorganised or catatonic behaviour.
○ Negative symptoms such as diminished emotional expression.
○ At least one of these must be A,B,C.
○ Criterion B:
○ Social/occupational dysfunction:
○ For a significant portion of time since the onset of the disturbance, one or more major areas of
functioning such as work, impersonal relations, or self-care are markedly below the level achieved
prior to the onset.
○ Criterion C
○ Duration:
○ Some of the signs of the disorder must last for at least 6 months. This must include at least 1
month of symptoms that meet criterion A.
Positive symptoms
○ Positive symptoms are atypical symptoms experienced in addition to normal experiences.
○ These symptoms include:
○ Hallucinations - bizarre, unreal perceptions of the environment that are usually auditory but may
also be visual, olfactory or tactile. Many schizophrenics report hearing a voice(s) telling them to do
something.
○ Delusions - bizarre beliefs that seem real to the person with schizophrenia, but they are not real.
Sometimes these delusions can be paranoid in nature. This often involves a belief that the person is being
followed or spied upon by someone. They may believe that their phone is tapped or that there are video
cameras hidden in their home. Delusions may also involve inflated beliefs about the person’s power and
importance.
○ Disorganised speech - Where the individual has problems organising his or her thoughts and this shows
up in their speech. They may slip from one topic to another. In extreme cases their speech may be so
incoherent that it sounds like complete gibberish.
○ Grossly disorganised and catatonic behavior - Includes the inability or motivation to initiate a task or to
complete it once it is started which leads to difficulties in daily living and can result in decreased interest
in personal hygiene. The individual may dress or act in ways that appear bizzare to other people.
Catatonic behaviours are characterised by a reduced reaction to the immediate environment, ridgid
postures or aimless motor activity.
, Negative symptoms
○ These reflect a loss of normal functions, which often persist even during periods of low positive
symptoms. These symptoms weaken the person’s ability to cope with everyday activities, affecting
their quality of life.
○ These symptoms include:
○ Speech poverty (alogia) - C haracterised by the lessening of speech fluency and productivity,
this is thought to reflect slowing or blocked thoughts. They may produce fewer words in a given
time on a task of verbal fluency. This may also be reflected in less complex syntax.
○ Avolition - A reduction of interests and desires as well as an inability to initiate and persist in
goal-directed behaviour. This is distinct from poor social function or disinterest, which can be the result of
other circumstances.
○ Affective flattening - A reduction in the range and intensity of emotional expression, including facial
expression, voice tone e.t.c. Compared to controls without this symptom, individuals show fewer body
and facial movements and smiles, and less co-verbal behaviour.
○ Anhedonia - A loss of interest or pleasure in all or almost all activities,or a lack of relativity to normally
pleasurable stimuli. It may be pervasive or it may be confined to a certain aspect of experience. Physical
anhedonia is the inability to experience physical pleasures. Social anhedonia is the inability to experience
pleasure from impersonal situations such as interacting with other people.
Reliability in diagnosis and classification
The diagnosis of schizophrenia must be r epeatable.
○ Clinicians must be able to reach the same conclusions at two different points in time - test retest reliability.
○ Different clinicians must reach the same conclusion - inter-rater reliability.
○ Inter-rater reliability is measured by a statistics called Kappa score. A kappa score of 0
.8 o
r above is
generally considered good. The diagnosis of schizophrenia had a kappa score of only 0.46.
Cultural differences in diagnosis
Research suggests there is a significant variation between countries when it comes to diagnosing schizophrenia.
○ Copeland gave 134 US and 194 british psychiatrists a description of a patient. 69% of the US psychiatrists
diagnosed schizophrenia, but only 2% of the british ones gave the same diagnosis.
○ Luhrmann interviewed 60 adults diagnosed with schizophrenia, 20 each in Ghana, India and the US. Many African
and Indian subjects reported positive experiences with their voices, describing them as playful and offering
advice, not one american did.
validity in diagnosis and classification
This refers to whether an observed effect is a genuine one a
nd the extent that a diagnosis represents something that is
real and d
istinct from other disorders.
Gender bias in diagnosis
Occurs when accuracy of diagnosis is dependent on the gender o
f an individual. The accuracy of diagnosis judgements
can vary for a number of reasons.
○ Broverman f ound that clinicians in the US equated mentally healthy “adult” behaviour with mentally healthy “male”
behaviour. As a result there was a tendency for women to be perceived as less mentally healthy, which could lead
to an incorrect diagnosis of schizophrenia.
Symptom overlap
Symptoms of a disorder may n
ot be unique to that disorder but also may be found in other disorders.
Classification of schizophrenia
○ Schizophrenia i s a type of psychosis characterised by a p rofound d isruption o
f cognition and emotion.
○ It is a severe mental disorder where contact with e xternal reality is lost.
○ It affects about 1% of the population at some point in their lifetime.
○ Most often diagnosed between 15-35, w ith men and women equally affected.
○ Not every patient displays all the symptoms.
Diagnosing schizophrenia
○ Diathesis stress model i s a classification and description of over 200 mental disorders, grouped in terms of their
common features. ICD i s more commonly used in Europe.
○ Criterion A:
○ Two or more of the following symptoms for a significant portion of time during a 1 month period:
○ Delusions.
○ Hallucinations.
○ Disorgansised speech.
○ Grossly disorganised or catatonic behaviour.
○ Negative symptoms such as diminished emotional expression.
○ At least one of these must be A,B,C.
○ Criterion B:
○ Social/occupational dysfunction:
○ For a significant portion of time since the onset of the disturbance, one or more major areas of
functioning such as work, impersonal relations, or self-care are markedly below the level achieved
prior to the onset.
○ Criterion C
○ Duration:
○ Some of the signs of the disorder must last for at least 6 months. This must include at least 1
month of symptoms that meet criterion A.
Positive symptoms
○ Positive symptoms are atypical symptoms experienced in addition to normal experiences.
○ These symptoms include:
○ Hallucinations - bizarre, unreal perceptions of the environment that are usually auditory but may
also be visual, olfactory or tactile. Many schizophrenics report hearing a voice(s) telling them to do
something.
○ Delusions - bizarre beliefs that seem real to the person with schizophrenia, but they are not real.
Sometimes these delusions can be paranoid in nature. This often involves a belief that the person is being
followed or spied upon by someone. They may believe that their phone is tapped or that there are video
cameras hidden in their home. Delusions may also involve inflated beliefs about the person’s power and
importance.
○ Disorganised speech - Where the individual has problems organising his or her thoughts and this shows
up in their speech. They may slip from one topic to another. In extreme cases their speech may be so
incoherent that it sounds like complete gibberish.
○ Grossly disorganised and catatonic behavior - Includes the inability or motivation to initiate a task or to
complete it once it is started which leads to difficulties in daily living and can result in decreased interest
in personal hygiene. The individual may dress or act in ways that appear bizzare to other people.
Catatonic behaviours are characterised by a reduced reaction to the immediate environment, ridgid
postures or aimless motor activity.
, Negative symptoms
○ These reflect a loss of normal functions, which often persist even during periods of low positive
symptoms. These symptoms weaken the person’s ability to cope with everyday activities, affecting
their quality of life.
○ These symptoms include:
○ Speech poverty (alogia) - C haracterised by the lessening of speech fluency and productivity,
this is thought to reflect slowing or blocked thoughts. They may produce fewer words in a given
time on a task of verbal fluency. This may also be reflected in less complex syntax.
○ Avolition - A reduction of interests and desires as well as an inability to initiate and persist in
goal-directed behaviour. This is distinct from poor social function or disinterest, which can be the result of
other circumstances.
○ Affective flattening - A reduction in the range and intensity of emotional expression, including facial
expression, voice tone e.t.c. Compared to controls without this symptom, individuals show fewer body
and facial movements and smiles, and less co-verbal behaviour.
○ Anhedonia - A loss of interest or pleasure in all or almost all activities,or a lack of relativity to normally
pleasurable stimuli. It may be pervasive or it may be confined to a certain aspect of experience. Physical
anhedonia is the inability to experience physical pleasures. Social anhedonia is the inability to experience
pleasure from impersonal situations such as interacting with other people.
Reliability in diagnosis and classification
The diagnosis of schizophrenia must be r epeatable.
○ Clinicians must be able to reach the same conclusions at two different points in time - test retest reliability.
○ Different clinicians must reach the same conclusion - inter-rater reliability.
○ Inter-rater reliability is measured by a statistics called Kappa score. A kappa score of 0
.8 o
r above is
generally considered good. The diagnosis of schizophrenia had a kappa score of only 0.46.
Cultural differences in diagnosis
Research suggests there is a significant variation between countries when it comes to diagnosing schizophrenia.
○ Copeland gave 134 US and 194 british psychiatrists a description of a patient. 69% of the US psychiatrists
diagnosed schizophrenia, but only 2% of the british ones gave the same diagnosis.
○ Luhrmann interviewed 60 adults diagnosed with schizophrenia, 20 each in Ghana, India and the US. Many African
and Indian subjects reported positive experiences with their voices, describing them as playful and offering
advice, not one american did.
validity in diagnosis and classification
This refers to whether an observed effect is a genuine one a
nd the extent that a diagnosis represents something that is
real and d
istinct from other disorders.
Gender bias in diagnosis
Occurs when accuracy of diagnosis is dependent on the gender o
f an individual. The accuracy of diagnosis judgements
can vary for a number of reasons.
○ Broverman f ound that clinicians in the US equated mentally healthy “adult” behaviour with mentally healthy “male”
behaviour. As a result there was a tendency for women to be perceived as less mentally healthy, which could lead
to an incorrect diagnosis of schizophrenia.
Symptom overlap
Symptoms of a disorder may n
ot be unique to that disorder but also may be found in other disorders.
