Diagnosis and Classification of SZ Flashcards
1
Q
What is schizophrenia?
A
- a serious mental disorder experienced by 1% of the world’s population where contact with reality & insight are impaired, example of psychosis
2
Q
What is classification?
A
- refers to the ability to identify a disorder, as different to all other disorders by identifying clusters of symptoms that occur together and classifying as one disorder
3
Q
What is diagnosis?
A
- refers to the ability to reliably diagnose a disorder based on symptoms someone has e.g. schizophrenia
4
Q
What are the two major systems for classification of mental disorder?
A
- The WHO ICD-10 and DSM-V (APA)
5
Q
How do the ICD-10 & DSM-V differ?
A
- ICD-10 (WHO classification system)
> two or more negative symptoms are needed when classifying schizophrenia & symptoms must be presence for a month - DSM-V (manual used by the APA)
> one positive symptom must be present for diagnosis & signs of disturbance should be apparent for at least 6 months
6
Q
What is meant by positive symptoms of schizophrenia?
A
- symptoms experienced in addition to normal experiences e.g. hallucinations & delusions
7
Q
What are the characteristics of hallucinations?
A
- positive symptom of SZ
- these are unusual sensory experiences
- some can be related to events in the environment or some random > e.g. voices heard either talking to or commentin on a person (auditory)
or person may also may see distorted facial expressions, or people or animals that are not there (visual)
8
Q
What are the characteristics of delusions?
A
- positive symptom of SZ (known as paranoia)> which are irrational beliefs
- e.g. delusions of grandeur > believing that you are an important historical figure such as Jesus
- persecutory delusion > believing that your going to be persecuted e.g. aliens watching you
- delusions of control > person believing that them and their Thoughts are being controlled by external source
9
Q
What is meant by negative symptoms of schizophrenia?
A
- symptoms that represent the loss of a usual experience e.g. avolition & speech poverty
10
Q
What are the characteristics of avolition?
A
- negative symptom of SZ > sometimes called apathy
- this is described as finding it difficult to begin or keep up with goal-directed activity > due to reduced motivation to carry out activities
- Andreasen > three signs of avolition = poor hygiene & grooming, lack of persistence in work or education & lack of energy
11
Q
What is the characteristics of speech poverty?
A
- negative symptom of SZ
- emphasis is on reduction in the amount & quality of speech
- may be accompanied by a delay in verbal response during a conversation > disorganised speech
12
Q
What is reliability?
A
- refers to the consistency of findings from an investigation or measuring device
13
Q
What is validity?
A
- the extent to which an observed effect is genuine and accurate
14
Q
What is a strength of the diagnosis of schizophrenia in terms of its reliability?
A
- its reliability is high
- this is assessed by looking at inter-rater reliability (whether two clinicians reach the same diagnosis for same individual) & test-retest reliability (when the same clinician reaches the same diagnosis for the same individual on two occasions)
- Osorio et al report excellent reliability for the diagnosis of SZ in 180 individuals using the DSM-5 > pairs of interviewers achieved inter-rater reliability of +.97 & test-retest reliability of +.92
- we can reasonably be sure that the diagnosis of SZ is consistently applied
15
Q
What is a limitation of the diagnosis of schizophrenia in terms of validity?
A
- its validity is low
- one way to assess is through criterion validity
- Cheneaux et al had two psychiatrists independently assess the same 100 clients using ICD-10 and DSM IV criteria & found that 68 were diagnosed with SZ under ICD system and 39 under DSM
- suggests SZ is either over or underdiagnosed according to the diagnostic system
16
Q
What is another limitation of diagnosis in terms of gender bias?
A
- existence of gender bias
- Since the 1980s men have been diagnosed with SZ more commonly than women
- One possible explanation is that women are underdiagnosed because they have closer relationships and hence get support (Cotton et al)
- leads to women with SZ often functioning better than men
- This underdiagnosis is a gender bias and means women may not therefore be receiving treatment & services that may benefit them
17
Q
What is another limitation of diagnosis in terms of cultural bias?
A
- the existence of culture bias
- Some symptoms of SZ particularly hearing voices, have different meanings in different cultures.
- e.g. in Haiti some people believe that hearing voices are communications from ancestors
- British people of African-Caribbean origin are up to 9x as likely to receive a diagnosis as white British people (Pinto and Jones)
- most likely explanation for this is culture bias in diagnosis of clients by psychiatrists from a different cultural background > leads to an overinterpretation of symptoms in black British people (Escobar 2012).
- means that British African-Caribbean people may be discriminated against by a culturally-biased diagnosis system
18
Q
What is another limitation of SZ diagnosis in terms of symptom overlap?
A
- limitation is symptom overlap with other conditions
- There is considerable overlap between the symptoms of SZ & the symptoms of other conditions
- e.g. both SZ & bipolar disorder involve + symptoms (delusions) & - symptoms (avolition)
- In terms of classification this suggests that SZ & bipolar disorder may not be two different conditions but variations of a single condition
- In terms of diagnosis it means that schizophrenia is hard to distinguish from bipolar disorder = unreliable
- As with co-morbidity, symptom overlap means that schizophrenia may not exist as a distinct condition
and that even if it does it is hard to diagnose. - So both its classification and diagnosis are flawed.
