Schizophrenia- symptoms and classification and diagnosis

Question 1

symptoms- diagnostic criteria from DSM-5 (2013)

Answer 1

must have 2 or more of: Delusions, hallucination, disorganised thinking (speech), grossly disorganized or catatonic behaviour, negative symptoms, each present for a significant portion of time during a 1 month period, at least one of these must be delusions hallucinations or disorganized thinking/speech.
must have ‘continuous signs of disturbance’ for at least 6 months.

unlike other mental disorders schizophrenia has no single defining symptom, instead they are diverse and each patients experience of them is unique in number and type of symptoms they have.

Question 2

delusions

Answer 2

fixed false belief resistant to change in the light of contrary evidence.
May include delusions of persecution e.g. belief that a group/organisation plans to harm/ harass them; reference or grandeur, external gestures/ environmental cues are directed at them/ that they are have fame/ wealth, thought withdrawal (outside force removing them) or insertion (alien thoughts created) and delusions of control (outside force acting on or manipulating thoughts)
they are considered bizarre if they are implausible, cannot be understood by same culture peers or if they don’t derive from ordinary life experiences.

Question 3

hallucinations

Answer 3

perception-like experiences without external stimuli.
commonly auditory- voices in head involuntary, need to be distinct from patients own thoughts whether familiar or unfamiliar voice.
they need to be distinguished from normal religious experience (those are not signs of sz)
shouldn’t be used on basis of diagnosis because these symptoms are common in related disorders too (e.g.??)

Question 4

disorganised thinking (speech)

Answer 4

disorganized through inferred from speech
switching of topics, irrelevance/word salad (incoherrence)
the symptom must be severe enough to interfere with normal communication because mildly disorganised speech is common and non specific.

Question 5

(grossly disorganised or) catatonic behaviour

Answer 5

disorganized = unpredictable unpredictable agitation or childlike silliness
catatonic behaviour= is a marked decrease in reactivity to the environment: including rigid posture, lack of verbal or motor responses, or negativism (resistance to instructions).

Question 6

negative symptoms

Answer 6

DIMINISHED EMOTIONAL RESPONSE
reduction in eye contact, facial expression, hand movements
AVOLITION; decrease in motivated self-initiated purposeful activities (lack of will to accomplish things) patients may show little interest in participating in social activities or work.

less common in other psychotic disorders so is one to look out for.

Question 7

DIAGNOSIS: reliability

Answer 7

consistency of diagnosis

inter-rater reliability 
klietman's 3 problems:
clinicians: subjectivity
patients: presentation
procedures: classification systems

unreliable diagnosis= invalid diagnosis

Question 8

validity

Answer 8

truth/ accuracy

Question 9

what are the two widely used classification systems for mental disorders

Answer 9

ICD & DSM

Question 10

ICD and produced by

Answer 10

international classification for disease

WHO

Question 11

DSM and produced by

Answer 11

diagnostic and statistical manual of mental disorders

American psychiatric association

Question 12

what’s a criticism of DSM

Answer 12

it pathologies human behaviour i.e it identifies more and more behaviours as ‘disorders’ meaning psychiatrists can make huge profits treating what are, in reality, not genuine disorders.

Question 13

what measure of patients functioning had been dropped from DSM 5 and what has replaced it

Answer 13

GAF scale replaced by WHODAS

Question 14

diagnostic criteria from DSM-5 (2013)

Answer 14

two or more of the 5 symptoms, each present for a significant portion of time during a 1 month period, At least one of these must be delusions, hallucinations or disorganised thinking. ‘continuous signs of disturbance’ for at least 6 months

Question 15

crow (1980)

Answer 15

made the distinction between two types of schizphrenia
type I- positive symptoms- something is in some way added to the sufferer’s personality
type II- negative symptoms- something is taken away from the sufferer’s personality

Question 16

subtypes of SZ

Answer 16

e.g paranoid, hebephrenic (disorganized) catatonic
however DSM has dropped the subtypes and ICD-11 will drop them. because trials have shown that there is a lack of reliability in diagnosis of the sub-types.

Question 17

what are kleitman’s 3 factors affecting reliability (consistency) of diagnosis

Answer 17

issues with the procedures e.g. use of classification systems
differences between clinicians; subjective interpretation
differences between patients;presentative

Question 18

Differences in procedures

e.g use of classification systems how does it affect reliability of diagnosis

Answer 18

different classification systems likely to make different diagnoses
cooper 1972 new yorkers diagnosed sz twice as often as londoners from the same videotaped clinical interview. the londoner diagnosed mania and depression twice as often.
DSM used predominantly in the US and a mixture elsewhere in the world.
ICD allow diagnosis with symptoms within the last month, while DSM insists on some symptoms in the preceding six months.

CHENIAUX et al (2009) found that rates of diagnosis of SZ using ICD (68/200) were significantly higher than when using DSM-IV (39/200).
Cheniaux traced this directly to there being no need for symptoms in the last 6 months in ICD.

Question 19

differences between clinicians; subjective interpretation

Answer 19

even with same classification systems being used, clincians may interpret them differently.
phrases in manuals are very open to interpretation e.g in DSM -5 delusions are defined as bizarre ‘if they are clearly implausible and not understandable to the same culture peers and do not derive from ordinary life experiences.’

MoJTABI AND NICHOLSON (first name bizzare, second name more ordinary) (1995) found weak inter-rater reliability (0.4) between clinicians in judgements of whether hallucinations were bizarre or not, this suggests that different doctors interpret the criteria differently.

Question 20

differences between patients; presentation

Answer 20

patients may present differently on different days, depedning on their mood and the variability of symptoms.
a diagnosis on one day could be different from that on another day, depending on the symptoms and their severity. patients may also react differently depending on the doctor (gender/age/ethnicity/appearance)

ppl respond best to those similar to them?
can’t change identity but can change personality- so warmth and understanding.

Question 21

improvements in reliability over time

Answer 21

early research on diagnosis showed worryingly low reliability.

Beck (1967) inter-rater reliability between two psychiatrists was 54% (agreed 54% of time for 154 ppl) using DSM- 2 ((COOPER ALSO FOUND POOR INTERRat RELI BETWEEN UK AND US PSYCHIATRISTS))

the first two DSM were much weaker than the subsequent editions; illnesses described in vague terms- low reliability as a result of their use.
these problems led to overhaul of DSM- reliability improved with DSM III in 1980 by removing vague description and blurred boundaries between disorders and by clarifying !!how many symptoms and of what type were required!!.
by DSM III 81% consistency of diagnoses, suggesting improvements

Question 22

what is a valid diagnosis

Answer 22

one that is correct!! in order for this 2 main conditions have to be satisfied:

• the illness has to be RELIABLY defined/classified and diagnosed
• the illness has to be VALIDLY defined or classified

Question 23

Validity in relation to reliability

Answer 23

Reliability is required for validity. consistency is a precondition for validity, but reliability is not guaranteed validity- can be consistently incorrect.
e.g.
ROSENHAN (1973) no pseudo patients had SZ (but reported they heard a voice saying ‘thud’. all but one received a diagnosis- doctors were reliable in diagnosis but were invalid. he used DSM 2 though so we know there have been improvements since then, but still demonstrates the need for validity not just reliability.

Question 24

why is SZ unique

Answer 24

unlike other illnesses there is no observable physiological indicator that can be objectivly measured in a laboratory, which makes it extremely genuine verification a diagnosis very difficult. can only observe behaviour

Question 25

how validity of classification relates to validity of diagnosis

Answer 25

SZ one of the most fiercely debated disorders
history of definition demonstrated how its definition had changed over time how there’s been great disagreement over how to define the illness.
lack of consistency in definition = problem of validity- if people disagree they cannot all be correct

for diagnosis to be valid we need to be confident that doctors are not just constant but right!
But the problem remains for diagnosing the actual illness because of the absence of the physiological marker.
we need to confident that the illness has been classified in a valid way.

Question 26

assessing validity of classification-

descriptive validity - are the symptoms right?

Answer 26

diversity of symptoms = difficult to define precisely
(major argument against the validity of the classification of the illness) there is no pathognomonic (defining) symptom of SZ (pointed out by kleitman).
boundaries between sz and depression are blurred they share symptoms e.g negative ones (lack of pleasure etc)

Bentall argues the diversity of symptoms means that SZ is a pointless label for what are independent symptoms. The label masks large differences between indiviuduals. to solve the issue the symptoms separately should be treated.

if symptoms do group together- can investigate by cluster analysis- which looks at whether symptoms co-occur- i.e. if someone with one symptom is at greater risk of developing another. (Liddle found that there were 3 clusters of symptoms - positive, negative and cognitive disorganisation) but subtypes were decided to be removed from DSM 5 due to subtype diagnosis being unreliable in trials.

Question 27

Aetiological validity- can we identify causes & mechanisms?

Answer 27

major disagreement on SZ causes and mechanisms!

((however anorexia’s causes and mechanisms are also debated but no one questions whether it is a real disorder.

e.g phobias psychologists broadly agree that there are acquired and maintained by classical and operant conditioning.))

Howes and Kapur (2008) argue pre-synaptic dysregulation of dopamine involved in all cases of SZ that have psychotic symptoms (hallucinations and delusions)
it is the common mechanism in all cases even if the initial cause of dysregulation may be different. for some it may be genetic for others is may be environment and for the most it’s likely to be a combination.

If restrict the disorder to simply psychotic symptoms due to DD then it’s defined in a clearer way and it has a greater chance of having aetiological validity- if supported by research.

Question 28

Predictive valifity- what is the prognosis /reaction to treatment

Answer 28

in a well-defined illness we should be able to describe how well the illness progresses over time and predict how they will react to treatments

about 1/3 of patients remain chronically ill, about a 1/3 recover from initial bouts of the illness and about 1/3 have periods of being relatively well.
this shows that patients have different histories and that it would be hard to predict who would have better outcomes

reaction to treatment escpecially drug treatments is very mixed. all drugs that have any effectiveness are those that target dopamine receptors but some are effective for some patients but not others and prognosis is unpredictable
rough percentages and generalisations

Question 29

Why is false positive worse than false negative

Answer 29

false negative:
People are often left undiagnosed anyway
Could argue that the rough percentages of effectiveness of treatment means that treatment may not have worked for the individual anyway/ nor the predictability
Patients have periods of good and bad health as it is
false positive :
more severe consequences- inappropriate treatment
inducing the illness/psychosis-sensitizing dopamine receptors (a theory)
side effects of treatment
labelling/stigmatism
(PERLMAN 2000 misdiagnosed adults with aspergers syndrome as having SZ and were given antipsychotics despite lack of positive symptoms!)
self fulfilling prophecy- becomes part of indignity and doctors will interpret behaviour consistent with diagnosis- reinforcing the illness.

Question 30

CROW (1980)

Answer 30

made a distinction between two types of SZ

type I- charactiersited by positive symptoms- some way adding to the sufferer’s personality

type II- characterised by negative symptoms- some way removing from the sufferer’s personality.

Question 31

Validity of classification relating to the validity of diagnosis

Answer 31

Since SZ possesses no phsioloigcal marker, like most other medical illnesses, it’s history of definition has been fiercely debated demonstrating that there is inconsistency (disagreement) between professionals. If people disagree they cannot all be correct which is the problem of validity.

Doctors must be not just consistent but correct too,
this makes verification of the illness very difficult because it means diagnosis has to solely rely on the validity of the classification system due to their being no physiological marker.