diagnosis and classification of schiz

Question 1

what is schizophrenia?

Answer 1

a severe mental illness where contact with reality and insight and impaired, an example of psychosis.

suffered by around 1% of the population. symptoms can interfere severely with everyday tasks - so many sufferers end up homeless or hospitalised.

Question 2

what are the two major systems for the classification of schizophrenia?

Answer 2

ICD-10
DSM-5

Question 3

how does the ICD-10 classify schiz?

Answer 3

recognises a range of subtypes of schizophrenia.

tends to be used in Europe.

patient need only present 2 negative symptoms (e.g. speech poverty and avolition).

Question 4

how does the DSM-5 classify schiz?

Answer 4

patient needs to present at least one positive symptom (e.g. hallucinations).

latest version has removed subtypes.

tends to be used in USA and Australia.

Question 5

what is a positive symptom?

Answer 5

positive symptoms are additional experiences beyond those of normal experiences. they include hallucinations and delusions.

Question 6

describe hallucinations.

Answer 6

a positive symptom of schizophrenia. they are sensory experiences of stimuli that have either no basis in reality or are distorted perceptions of how things really are.

e.g. seeing people that are actually not there, or hearing voices criticising them.

Question 7

describe delusions.

Answer 7

a positive symptom of schizophrenia. also known as paranoia. they involve irrational beliefs that have no basis in reality.

one of the delusions experienced is paranoid delusions - where an individual believes that something, or someone, is deliberately trying to hurt, manipulate or even kill them.

another is the delusion of grandeur - where they believe they have some imaginary power of authority, such as thinking they are on a mission from god.

Question 8

what is a negative symptom?

Answer 8

negative symptoms involve the loss of usual abilities and experiences. examples include speech poverty and avolition.

Question 9

describe avolition.

Answer 9

a negative symptom of schizophrenia. it involves sharply reduced motivation to carry out tasks and finding it hard to begin or keep up with a goal-related activity.

sings of avolition include - poor hygiene and grooming, lack of energy and lack of persistence in education or work.

Question 10

describe speech poverty.

Answer 10

a negative symptom of schizophrenia. involves reduced frequency and quality of speech. sometimes accompanied by a delay in the sufferers verbal responses during a conversation.

Question 11

outline reliability as an issue with the C&D of schz.

Answer 11

One issue with the classification and diagnosis of schizophrenia is that of reliability. Reliability is to do with the consistency of diagnosis.

Two or more mental health professionals should arrive at the same diagnosis for the same patients when diagnosing schizophrenia - known as inter-rater reliability.

A mental health professional should also make the same diagnosis of schizophrenia on separate occasions from the same information from a patient.

Question 12

describe what has attempts to improve reliability in the C&D of scz led too?
why is this a problem?

Answer 12

Attempts to improve the reliability of diagnosis of schizophrenia over the years have led to updates to the two main classification systems used in Western medicine, the ICD 10 and DSM V.

Therefore, there are slight differences with how it is classified.

This immediately raises issues with reliability and validity of diagnosis, as if different clinicians are using different classification systems with different criteria, there is immediately disagreement on how to diagnose schizophrenia.

Question 13

discuss reliability as an issue with the C&D of schz.

Answer 13

There is some evidence to suggest that the diagnosis of schizophrenia is reliable.

Jakobsen et al. (2005) tested the reliability of ICD-10 using 100 Danish patients with a history of psychosis.

They found an agreement rate of 98% between professionals. This suggests that the diagnosis of schizophrenia has high inter-rater reliability.

HOWEVER -
this study was only carried out in one country so the findings may not apply to the diagnosis of schizophrenia in other places, limiting how far the findings can support the reliability of schizophrenia.

HOWEVER -

there is also evidence to suggest that the diagnosis of schizophrenia is not reliable.

Cheneaux et al. (2009) had two psychiatrists independently diagnose 100 patients using both DSM and ICD criteria.

They found inter-rate reliability to be poor. One psychiatrist diagnosed 26 cases of schizophrenia according to DSM and 44 according to ICD. The other diagnosed 13 according to DSM and 24 according to ICD.

This study suggests that the diagnosis of schizophrenia is not reliable.

HOWEVER -
this study used the previous version of DSM (DSM-4) and it could be argued that the inter-rater reliability may be better when the current version of DSM (DSM-5) is used.

therefore the findings are limited in how far they can dispute the reliability of the current classification of schz.

Question 14

outline validity as an issue with the the C&D of schz.

Answer 14

A second issue with the classification and diagnosis of schizophrenia is that of validity.

Validity refers to how accurate a diagnosis is. Different classification systems (e.g. ICD-10 and DSM-5) should arrive at the same diagnosis for the same patients and patients with schizophrenia should differ in symptoms from patients with other disorders.

A valid diagnosis should also lead to successful treatment.

Question 15

discuss validity as an issue of diagnosis of schz.

Answer 15

there is evidence to suggest that the diagnosis of schizophrenia is not valid.

Rosenhan (1973) sent 8 volunteers who did not suffer from mental illness to different mental hospitals, claiming that they heard voices. All were admitted and it took between 7 and 52 days for them to be released. They then informed hospitals to expect pseudopatients over a three-month period. None were sent, but hospitals suspected that 83 of 193 genuine patients were fake.

This study suggests that it is difficult for professionals to diagnose schizophrenia in patients as ‘normal’ patients were assumed to have schizophrenia, as well as genuinely ill patients being assumed to be ‘normal’.

this suggests that the diagnosis of schz does lack validity - a weakness of diagnosis.

HOWEVER -
this study is over 40 years old and the diagnostic criteria used in this study would not be used today when diagnosing schizophrenia, meaning that this lacks temporal validity and the issues that Rosenhan found are unlikely to be as severe with modern diagnostic criteria and clinicians.

therefore the findings are limited in what they can tell us about the validity of current diagnostic criteria.

Question 16

discuss co-morbidity as an issue with C&D of schz.

Answer 16

One reason for problems with validity of diagnosis may be co-morbidity. Schizophrenia is commonly diagnosed with other conditions.

In one review, Buckley et al. (2009) concluded that around half of people with a diagnosis of schizophrenia also have a diagnosis of depression (50%) or substance abuse (47%). Post-traumatic stress disorder also occurred in 29% of cases and OCD in 23%. 

This may mean that it can be difficult for clinicians to discriminate between disorders. Where two conditions are frequently diagnosed together, it calls into question the validity of the classification of both illnesses.

In terms of classification, it may be that, if very severe depression looks a lot like schizophrenia and vice versa, then they might be better seen as a single condition.

this confusing picture calls is a weakness of the diagnosis and classification of schz.

Question 17

discuss symptom overlap as an issue with C&D of schz.

Answer 17

A further complication in diagnosing schizophrenia is symptom overlap. There is considerable overlap between the symptoms of schizophrenia and other conditions.

For example, both schizophrenia and bipolar disorder involve positive symptoms like delusions and negative symptoms like avolition.

This again calls into question the validity of both the classification and diagnosis of schizophrenia.

Under ICD a person might be diagnosed with schizophrenia - however, many of the same individuals would receive a diagnosis of bipolar disorder according to DSM criteria.

This is an issue of validity of diagnosis and classification.

Question 18

discuss culture bias as an issue of diagnosis of schz.

Answer 18

A further issue with the diagnosis of schizophrenia is culture bias.

Reliability of diagnosis in schizophrenia is challenged by the finding that there is massive variation between countries.

African Americans and English people of Afro-Caribbean origin are several times more likely than white people to be diagnosed with schizophrenia.

Given that rates in Africa and the West Indies are not particularly high, this is almost certainly not due to genetic vulnerability. Instead, diagnosis seems to be beset with issues of culture bias.

There may be several factors involved - one issue is that positive symptoms such as hearing voices may be more acceptable in African cultures because of cultural beliefs in communication with ancestors, and thus people are more ready to acknowledge such experiences. but when reported to a psychiatrist from a different cultural tradition these experiences are likely to be seen as bizarre and irrational.

ADDITIONALLY -
Escobar (2012) has pointed out that (overwhelmingly white) psychiatrists may tend to over-interpret symptoms and distrust the honesty of Afro-Caribbeans during diagnosis.

this suggests that culture bias is a huge weakness of the reliability and validity of diagnosis of schz.

Question 19

discuss gender bias as an issue with the diagnosis of schz.

Answer 19

another issue is that there are gender biases in the diagnosis of schizophrenia.

Longenecker et al. (2010) reviewed studies of the prevalence of schizophrenia and concluded that since the 1980s men have been diagnosed with schizophrenia rather more often than women (prior to this there appears to have been no difference).

This may simply be because men are more genetically vulnerable to developing schizophrenia than women.

However, another possible explanation is gender bias in the diagnosis of schizophrenia. It appears that women typically function better than men, being more likely to work and have good family relationships (Cotton et al. 2009).

This high functioning may explain why some women have not been diagnosed with schizophrenia where men with similar symptoms might have been; their better interpersonal functioning may bias practitioners to under-diagnose schizophrenia, either because symptoms are masked altogether by good interpersonal functioning, or because the quality of interpersonal functioning makes the case seem too mild to warrant a diagnosis.

this suggests that gender bias is an issue with the diagnosis of schz, calling into question its validity.