Schizophrenia
Clinical characteristics
Positive symptoms
= an excess/distortion of normal/usual functions. These are ‘added’
behaviours or experiences.
Delusions – Hallucinations – Þ Thought insertion,
withdrawal or broadcast –
Þ Delusions of grandeur: Þ Additional sensory thoughts aren’t their own &
the sufferer believes experiences (smell/visual). instead have been
they’re someone E.g., seeing things that planted
important i.e., Jesus or aren’t there or seeing
has some special images in a distorted way Þ Incoherent/disorganised
powers speech - Sufferer’s speech
Þ Auditory hallucinations: goes in
Þ Paranoid delusions: voices are heard (mostly every direction without
belief that others want very critical or order the following a logical &
to harm the sufferer sufferer to do something). coherent thread (makes it
70% have auditory. impossible for others to
understand).
Negative symptoms
= refer to a loss of usual functioning – aspects of behaviour/personality lost
Þ Catatonic behaviour - might be motionless Þ Avolition: loss of interest in normal
for long periods of time. Repetitive & goals/reduction of goal-directed activity, lack
aimless behaviour (mannerism). of motivation & drive. Makes it difficult to
work, maintain personal hygiene, get out of
Þ Disorganised behaviour: Severe disruption bed
in the ability to perform daily living
activities, such as showering, dressing, Þ Affective Flattening: No emotional response
preparing meals. can be elicited to any stimulus; face is
immobile, eyes are lifeless, speech is toneless,
Þ Inappropriate affect: Silliness and laughter often staring vacantly.
which are out of context, e.g., laughing
when hearing terrible news. Þ Apathy: Feeling drained of energy & unable
to initiate/complete course of action.
Þ Anhedonia: A lack of interest in almost all
activities, or a lack of reactivity to usually Þ Cataleptic stupor: Standing motionless like a
pleasant stimuli. statue in bizarre postures.
, Duration – under DSM-IVR (diagnostic Statistical Manual) the diagnosis of
schizophrenia requires at least 1 month duration of 2 or more positive symptoms.
Reliability & Validity in the Diagnosis and Classification of Schizophrenia
Diagnostic reliability à Inter-rater reliability is measured by a
à refers to consistency of diagnosis, it must kappa score.
be repeatable.
A score of 1 = perfect correlation
Clinicians should come to same conclusion at A score of 0 = no correlation.
2 different points of time (test, retest reliability)
or different clinicians should reach the same A kappa score of 0.7 is generally
conclusions (inter-rater reliability). considered to be good.
Inter-rater reliability = the extent to which In the DSM –V field trials Regier et al (2013)
different assessors will arrive at the same found the diagnosis of SZ only had a kappa
conclusion when diagnosing the same score of 0.46.
patient.
Cultural Differences in the Diagnosis of SZ –
1 of main characteristics of SZ is ‘hearing voices’ &
this also seems to be influenced by cultural
Research suggests there’s significant environment.
variation between countries when it
comes to diagnosing SZ - culture has àLuhrman interviewed 60 adults with SZ (20 from
an impact on the diagnosis process. Ghana, 20 from India & 20 from the US). Each was
asked about the voices they heard.
à Copeland (1971) gave 134 US & 194
British psychiatrists a description of a à Many of the African & Indian ppts reported
patient, 66% of the US psychiatrists positive experiences with their voices (described
diagnosed SZ but only 2% of British them as playful/offering advice) but those in US
ones did. were more likely to describe them as hateful/violent.
à Luhrman suggests that the ‘harsh’ voices
common in the West may not be an inevitable
feature of SZ but more a cultural one.
, AO3
Criticism regarding the reliability - for a
diagnosis of SZ only 1 characteristic is
required if ‘delusions are bizarre’ - creates an
issue in determining what we consider to be
Support of influence of culture - Barnes
bizarre as it’s a very subjective term.
found that the prognosis for members of
ethnic minority groups may be more
Mojtabi & Nicholson asked 50 senior
positive than for majority members. The
psychiatrists in the US to differentiate
ethnic culture hypothesis predicts ethnic
between bizarre & non-bizarre delusions.
minorities experience less distress
Inter-rater reliability was found to be as low
associated with mental illness because
as 0.4 - this forced the researchers to
of the positive characteristics & social
conclude that even this central diagnostic
structures that exist in most ethnic
criteria lacks sufficient reliability for
minority cultures. Brekke supports this &
distinguishing between schizophrenic & non-
conducted a study involving 184
schizophrenic patients.
individuals diagnosed with SZ or SZ
spectrum disorders. This sample was
drawn from 2 non-white minority groups
(African & Latino) & a majority group
(white American) - found the non- However despite claims that the
DSM III and later versions (spanning
minority members were consistently
more symptomatic than members of the 30 years of updates) are more
2 ethnic minority groups; therefore, reliable there is little evidence that
supporting the ethnic culture hypothesis. this is indeed the case. Whaley
(2011) found an inter-rater reliability
of only 0.11
However, Rosenhan’s study shows that reliability of diagnosis is
questionable & is influenced by expectations & situational factors.
E.g., in this study once ppts had been admitted to the institutes
every behaviour they did was seen as a sign of SZ. When taking
notes about what was happening on the wards, the ppts were
described as ‘excessive handwriting’ which was seen as a
behavioural symptom of SZ.
If schizophrenia is diagnosed inconsistently, could be problematic as it may be over
or under-diagnosed by psychiatrists, meaning patients will be incorrectly labelled as
‘schizophrenic’ or not diagnosed - meaning they won’t receive the treatment they
need.
Clinical characteristics
Positive symptoms
= an excess/distortion of normal/usual functions. These are ‘added’
behaviours or experiences.
Delusions – Hallucinations – Þ Thought insertion,
withdrawal or broadcast –
Þ Delusions of grandeur: Þ Additional sensory thoughts aren’t their own &
the sufferer believes experiences (smell/visual). instead have been
they’re someone E.g., seeing things that planted
important i.e., Jesus or aren’t there or seeing
has some special images in a distorted way Þ Incoherent/disorganised
powers speech - Sufferer’s speech
Þ Auditory hallucinations: goes in
Þ Paranoid delusions: voices are heard (mostly every direction without
belief that others want very critical or order the following a logical &
to harm the sufferer sufferer to do something). coherent thread (makes it
70% have auditory. impossible for others to
understand).
Negative symptoms
= refer to a loss of usual functioning – aspects of behaviour/personality lost
Þ Catatonic behaviour - might be motionless Þ Avolition: loss of interest in normal
for long periods of time. Repetitive & goals/reduction of goal-directed activity, lack
aimless behaviour (mannerism). of motivation & drive. Makes it difficult to
work, maintain personal hygiene, get out of
Þ Disorganised behaviour: Severe disruption bed
in the ability to perform daily living
activities, such as showering, dressing, Þ Affective Flattening: No emotional response
preparing meals. can be elicited to any stimulus; face is
immobile, eyes are lifeless, speech is toneless,
Þ Inappropriate affect: Silliness and laughter often staring vacantly.
which are out of context, e.g., laughing
when hearing terrible news. Þ Apathy: Feeling drained of energy & unable
to initiate/complete course of action.
Þ Anhedonia: A lack of interest in almost all
activities, or a lack of reactivity to usually Þ Cataleptic stupor: Standing motionless like a
pleasant stimuli. statue in bizarre postures.
, Duration – under DSM-IVR (diagnostic Statistical Manual) the diagnosis of
schizophrenia requires at least 1 month duration of 2 or more positive symptoms.
Reliability & Validity in the Diagnosis and Classification of Schizophrenia
Diagnostic reliability à Inter-rater reliability is measured by a
à refers to consistency of diagnosis, it must kappa score.
be repeatable.
A score of 1 = perfect correlation
Clinicians should come to same conclusion at A score of 0 = no correlation.
2 different points of time (test, retest reliability)
or different clinicians should reach the same A kappa score of 0.7 is generally
conclusions (inter-rater reliability). considered to be good.
Inter-rater reliability = the extent to which In the DSM –V field trials Regier et al (2013)
different assessors will arrive at the same found the diagnosis of SZ only had a kappa
conclusion when diagnosing the same score of 0.46.
patient.
Cultural Differences in the Diagnosis of SZ –
1 of main characteristics of SZ is ‘hearing voices’ &
this also seems to be influenced by cultural
Research suggests there’s significant environment.
variation between countries when it
comes to diagnosing SZ - culture has àLuhrman interviewed 60 adults with SZ (20 from
an impact on the diagnosis process. Ghana, 20 from India & 20 from the US). Each was
asked about the voices they heard.
à Copeland (1971) gave 134 US & 194
British psychiatrists a description of a à Many of the African & Indian ppts reported
patient, 66% of the US psychiatrists positive experiences with their voices (described
diagnosed SZ but only 2% of British them as playful/offering advice) but those in US
ones did. were more likely to describe them as hateful/violent.
à Luhrman suggests that the ‘harsh’ voices
common in the West may not be an inevitable
feature of SZ but more a cultural one.
, AO3
Criticism regarding the reliability - for a
diagnosis of SZ only 1 characteristic is
required if ‘delusions are bizarre’ - creates an
issue in determining what we consider to be
Support of influence of culture - Barnes
bizarre as it’s a very subjective term.
found that the prognosis for members of
ethnic minority groups may be more
Mojtabi & Nicholson asked 50 senior
positive than for majority members. The
psychiatrists in the US to differentiate
ethnic culture hypothesis predicts ethnic
between bizarre & non-bizarre delusions.
minorities experience less distress
Inter-rater reliability was found to be as low
associated with mental illness because
as 0.4 - this forced the researchers to
of the positive characteristics & social
conclude that even this central diagnostic
structures that exist in most ethnic
criteria lacks sufficient reliability for
minority cultures. Brekke supports this &
distinguishing between schizophrenic & non-
conducted a study involving 184
schizophrenic patients.
individuals diagnosed with SZ or SZ
spectrum disorders. This sample was
drawn from 2 non-white minority groups
(African & Latino) & a majority group
(white American) - found the non- However despite claims that the
DSM III and later versions (spanning
minority members were consistently
more symptomatic than members of the 30 years of updates) are more
2 ethnic minority groups; therefore, reliable there is little evidence that
supporting the ethnic culture hypothesis. this is indeed the case. Whaley
(2011) found an inter-rater reliability
of only 0.11
However, Rosenhan’s study shows that reliability of diagnosis is
questionable & is influenced by expectations & situational factors.
E.g., in this study once ppts had been admitted to the institutes
every behaviour they did was seen as a sign of SZ. When taking
notes about what was happening on the wards, the ppts were
described as ‘excessive handwriting’ which was seen as a
behavioural symptom of SZ.
If schizophrenia is diagnosed inconsistently, could be problematic as it may be over
or under-diagnosed by psychiatrists, meaning patients will be incorrectly labelled as
‘schizophrenic’ or not diagnosed - meaning they won’t receive the treatment they
need.
