Diagnosing And Classiifcation - A03

Question 1

Good reliability

Answer 1

P) One strength of the diagnosis of schizophrenia is its reliability.
E) Reliability means consistency. A psychiatric diagnosis is said to be reliable when different diagnosing clinicians reach the same diagnosis for the same individual (inter-rater reliability) and when the same clinician reaches the same diagnosis for the same individual on two occasions (test-retest reliability).
E) Prior to DSM-5, reliability for schizophrenia diagnosis was low but this has now improved. Flávia Osório et al. (2019) report excellent reliability for the diagnosis of schizophrenia in 180 individuals using the DSM-5. Pairs of interviewers achieved inter-rater reliabilty of + 97 and test-retest reliability of +.92.
L) This means that we can be reasonably sure that the diagnosis of schizophrenia is consistently applied.

Question 2

Low validity

Answer 2

P) One limitation of the diagnosis of schizophrenia is its validity.
E) In general validity concerns whether we assess what we are trying to assess. One way to assess validity of a psychiatric diagnosis is criterion validity.
E) Elie Cheniaux et al. (200g) had two psychiatrists independently assess the same 100 clients using ICD-10 and DSM-IV criteria and found that 68 were diagnosed with schizophrenia under the ICD system and 39 under DSM.
L)This suggests that schizophrenia is either over- or underdiagnosed according to the diagnostic system. Either way this suggests that criterion validity is low.

Question 3

Co-morbidity

Answer 3

P) Another limitation of schizophrenia diagnosis is its co-morbidity with other conditions.
E) If conditions occur together a lot of the time then this calls into question the validity of their diagnosis and classification because they might actually be a single condition. Schizophrenia is commonly diagnosed with other conditions.
E) For example, one review found that about half of those diagnosed with schizophrenia also had a diagnosis of depression or substance abuse (see research by Buckley et al. on the right).
L) This is a problem for classification because it means schizophrenia may not exist as a distinct condition, and is a problem for diagnosis as at least some people diagnosed with schizophrenia may have unusual cases of conditions like depression.

Question 4

Gender bias

Answer 4

P) A further limitation of schizophrenia diagnosis is the existence of gender bias.
E) Since the 1980s men have been diagnosed with schizophrenia more commonly than women (a ratio of 1.4:1, Fischer and Buchanan 2017).
E) One possible explanation for this is that women are less vulnerable than men, perhaps because of genetic factors. However it seems more likely that women are underdiagnosed because they have closer relationships and hence get support (Cotton et al. 2009). This leads to women with schizophrenia often functioning better than men.
L) This underdiagnosis is a gender bias and means women may not therefore be receiving treatment and
services that might benefit them.

Question 5

Culture bias

Answer 5

P) A further limitation of schizophrenia diagnosis is the existence of culture bias.
Some symptoms of schizophrenia, particularly hearing voices, have different meanings in different cultures.
E) For example in Haiti some people believe that voices actually are communications from ancestors. British people of African-Caribbean origin are up to nine times as likely to receive a diagnosis as white British people (Pinto and Jones 2008), although people living in African-Caribbean countries are not, ruling out a genetic vulnerability.
E) The most likely explanation for this is culture bias in diagnosis of clients by psychiatrists from a different cultural background. This appears to lead to an overinterpretation of symptoms in black British people (Escobar 2012).
L) This means that British African-Caribbean people may be discriminated against by a culturally-biased
diagnostic system.

Question 6

Symptom overlap

Answer 6

P) A final limitation of schizophrenia diagnosis is symptom overlap with other conditions.
There is considerable overlap between the symptoms of schizophrenia and the symptoms of other conditions.
E) For example, both schizophrenia and bipolar disorder involve positive symptoms (such as delusions) and negative symptoms (such as avolition). In terms of classification this suggests that schizophrenia and 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.
E) 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.
L) So both its classification and diagnosis are flawed.