diagnosis and classification of schizophrenia

Question 1

schizophrenia is characterised by a?

Answer 1

profound disruption of cognition and emotion which affects language, thought, perception and sense of self.

Question 2

what type of disorder is schizophrenia?

Answer 2

a though disorder.

Question 3

what is the prevalence (people in the population)?

Answer 3

-men are more likely to suffer than women
-the lifetime prevalence of schizophrenia is 1%
-it ranks among top 10 causes of disability in the world
-it is more commonly diagnosed in cities rather than countrysides, and in working-class rather than middle-class.
-the onset is typically in late adolescence and early adulthood

Question 4

how is the diagnosis and classification done?

Answer 4

-identifying clusters of symptoms that occur together and classifying this as one disorder.
-diagnosis then becomes possible by identifying symptoms and decing what disorder a person has.

Question 5

how is the classification done by using DSM V?

Answer 5

a person must have at least 2 of the following symptoms most of the time during a one month period, with some level of disturbance being present over 6 months
-delusions
-hallucinations
-disorganised speech
-extremely disorganised behaviour
-catatonic behaviour, which can range from a coma-like daze to bizarre, hyperactive behaviour
-negative symptoms, which relate to reduced ability or lack of ability to function normally
at least one of these has to be delusions, hallucinations or disorganised speech.

Question 6

how is the classification done by using ICD-10?

Answer 6

the normal requirement for a diagnosis is that a minimum of one very clear symptom (and usually two or more if less clear-cut) should ha e been clearly present for most of the time during a period of one month or more.
(two or more negative symptoms are enough)

Question 7

what are the 7 types of schizophrenia as defined by the ICD-10?

Answer 7

• paranoid (prominent hallucinations and delusions and no inconspicuous affective symptoms)
• hebephrenic (prominent affective changes and thought disorder)
• catatonic (prominent psychomotor disturbances)
• undifferentiated (meets general diagnostic criteria, but doesn’t conform to a specific type)
• post-schizophrenia depression (a depressive episode following a schizophrenic episode)
• residual (chronic stage with long-term negative symptoms)
• simple (without hallucinations or delusions; characterised by negative symptoms without preceding psychosis)

Question 8

what are positive symptoms?

Answer 8

those that appear to reflect an excess or distortion of normal functions.

Question 9

what are negative symptoms?

Answer 9

those that appear to reflect a diminution or loss of normal functions.

Question 10

what are hallucinations and are they positive or negative?

Answer 10

hallucinations are unusual sensory experiences that have either no basis in reality or are distorted perceptions of things that are there. some examples include hearing voices that are often negative or criticising them or see distorted facial expressions.

• are positive

Question 11

what are delusions and are they positive or negative?

Answer 11

delusions involve beliefs that have no basis in reality or are irrational, tending to make those who suffer with schizophrenia believe they are historical figures or act in ways which make sense to them, but bizarre to others.
- positive

Question 12

what is avolition and is it a positive or negative symptom?

Answer 12

avolition refers to those who are suffering and how they may begin to experience difficulties or struggles with goal-directed activities such as poor hygiene or becoming unmotivated or unwilling to work.
- negative

Question 13

what is speech poverty and is it a negative or positive symptom?

Answer 13

a reduction in the amount and quality of speech accompanied by a delay in the persons verbal responses during conversations.
- negative.

Question 14

Carson (1991)

Answer 14

claimed the issue of reliability in the classification and diagnosis in the DSM III has been resolved leading to more agreement in diagnosis.

Question 15

Cheniaux et al (2009)

Answer 15

-compared the inter-rater reliability of the diagnosis of sz across DSM and ICD
-asked two psychiatrists to independently diagnose 200 patients using both measures
-found to be above +0.50 for both classificatory systems
-Sz was more frequently diagnosed with ICD 10 rather than DSM-IV criteria.

Question 16

how can Cheniaux et al (2009) study be used as an evaluation point?

Answer 16

supports that the diagnosis and classification are unreliable and not valid.

Question 17

Motjabi and Nicholson (1995)

Answer 17

found that bizarre delusions were not a reliable method of distinguishing between schizophrenic and non-schizophrenic patients: when 50 senior US psychiatrists were asked to differentiate between bizarre and non-bizarre delusions, IRR was just +.40

Question 18

Bell at al (2006)

Answer 18

note that only a small fraction of patients received their schizophrenia diagnosis because of the presence of bipolar disorder (4%-8%)

Question 19

Wilks et al (2003)

Answer 19

• gave 2 alternate versions of the test (RBANS) to Sz patients over intervals varying between 1-134 days and found a reliability rating of +0.84

Question 20

Prescott et al (1986)

Answer 20

analysed the test-retest reliability of several measurements of attention of information processing in 14 chronic sz finding stable measurements over a 6-month period.

Question 21

although reliability for the diagnosis of sz is not perfect, what does it give practitioners?

Answer 21

common language, permitting communication of research ideas and findings which may ultimately lead to a better understanding of the disorder and the development of better treatments.

Question 22

Osorio et al (2019)

Answer 22

• report excellent reliability for the diagnosis of sz in 180 individuals using the DSM- 5.
• pairs of interviews achieved great inter-rater validity of +.97 and test-retest reliability of +.92

Question 23

what is meant by validity in terms of Sz?

Answer 23

the diagnosis is measuring a real and distinct disorder clear from any other disorder.

Question 24

what is criterion validity and how can we correlate this with the ICD 10 and DSM V?

Answer 24

-this is a measure of validity which measures different assessment systems and if they accurately measure the same diagnosis for the same patient.
- as sz is much more likely to be diagnosed with ICD than DSM it is either over-diagnosed in ICD or under-diagnosed in DSM, meaning it has poor validity as they are clearly not measuring the same thing.

Question 25

Klosterkotter et al (1994)

Answer 25

• assessed 489 psychiatric admissions to a German hospital to determine whether + or - symptoms were more valid for a diagnosis to be made
• found that positive symptoms were more valid as they are much easier to spot.

Question 26

what is co-morbidity?

Answer 26

this is where two or more conditions occur together, and are referred to as comorbidity rates. as such, if conditions occur together a lot of the time, then they may possibly be the same condition.

Question 27

schizophrenics commonly have other conditions, these include?

Answer 27

drug/alcohol abuse (47%)
anxiety, depression (50%)
PTSD (29%)
OCD (23%)

Question 28

Weber et al (2009) ev

Answer 28

• a major negative consequence of being diagnosed with schizophrenia is that patients receive a lower standard of medical care, because of comorbidity, which affects their prognosis (cause of the condition)
• examined nearly 6 mil hospital discharge records finding psychiatric and behaviour related diagnoses to account for 45% of comorbidity.
  -the poor level of functioning as seen in schizophrenics may be more to do with their untreated comorbid conditions than the sz itself.

Question 29

Fischer + Budchanan (2017)

Answer 29

since the 1980’s, men have been diagnosed more than women.

Question 30

Cotton et al (2009)

Answer 30

women may be seen as less vulnerable than men, potentially due to genetic factors or that they have closer relationships and hence can get support.

Question 31

Copeland (1971)

Answer 31

• gave 134 US and 194 UK psychiatrists a description of a patient.
  -69% of US psychiatrists diagnosed sz but only 2% of UK psychiatrists did.

Question 32

Escobar (2012) explaining cultural bias

Answer 32

Afro-Caribbean living in the UK are 10 times more likely to be diagnosed with sz, compared to white brits.
-explains it by suggesting that it is most likely cultural bias in diagnosis of clients by psychiatrists from a different cultural background, appearing to lead an overinterpretation of symptoms in black british.

Question 33

what is symptom overlap and why is this an issue?

Answer 33

where many symptoms of schizophrenia are also seen in other disorders. for example, schizophrenia and bipolar may not be two different conditions but variations of the one. therefore questioning the validity of diagnosis and classification.

Question 34

Ophoff et al (2011)

Answer 34

• assessed genetic material from 50,000 participants to find that of 7 gene locations on the genome associated with schizophrenia, three of them are also associated with bipolar, suggesting a genetic overlap between the two disorders and a reason for the symptom overlap.