Issues in diagnosis

Co morbidity

The occurrence of two illnesses or conditions together

It is a problem because: 1. 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 conditions, and also calls into question whether they have been diagnosed correctly and produces a very confusing picture as schizophrenia may not exist as a single condition, 2. there are poorer overall outcomes as only one condition is focused on

Evidence- Buckley et al - 50% of people diagnosed with SZ also have depression, 47% of people diagnosed with SZ also have substance abuse problems

Swets et al - conducted a meta analysis and found that 12% of people diagnosed with SZ also have OCD and in 25% of the cases the symptoms are severe. Considering how rare these disorders are the fact that they occur together in higher than chance would suggest

Co morbidity- evaluations

Van dee et al- found that the type of co morbidity you had greatly impacted remission. Depression seems to effect it the most- this is valuable information as it could help treatment

Peng et al- foudn that medication prescribed can have negative impact on the other disorder (e.g. antipsychotics can effect heart disorders) So co morbidity is an issue as treatment becomes a lot more challenging

Symptom overlap

There is considerable overlap of symptoms of schizophrenia and other conditions (share symptoms)

It is a problem: 1. Ellason and Ross found that people with DID have more symptoms of SZ than people with SZ- so how can we be sure that they are being diagnosed correctly, 2. Read - symptom overlap is so common that most SZ an be diagnosed with another disorder, this calls into question the validity of the criteria

Evidence- Bipolar disorder- both SZ and bipolar disorder involve positive symptoms such as delusions, however people with bipolar have less severe delusions but what does less severe look like?

Schizoaffective disorder- this disorder was introduced to classify someone with SZ as well as severe mood disorders, however evidence has found that people with this disorder can have episodes of severe psychotic symptoms but no mood disorder so is it SZ or not

Symptom overlap- evaluations

Misdiagnosis - Gara- if misdiagnosed there could be severe consequences. For example people who have bipolar need mood stabilisers and people with depression may end up with severe side effects. This suggests that symptom overlap can have very dangerous consequences

Missed opportunities for early intervention- early intervention for SZ is extremely valuable and can even effect the length of suffering and how people cope with it. Symptom overlap hinders this as in the early stages the symptoms overlap with anxiety disorders

Cultural bias

The tendency to judge people in terms of your own cultural assumptions

It is a problem because:

Can lead to under or over diagnosis and incorrect treatment

Evidence- Pinto et al - British people of African- Caribbean origins are nine times more likely to receive a diagnosis of SZ- it is not so high in African Caribbean countries so it cannot be genetic

Copeland- gave 134 US psychiatrists and 194 British psychiatrists a description of a patient. 69% of the US psychiatrists gave a diagnosis of SZ compared to 2% of the British

Why is there so much over diagnosis- Afriklen- hearing voices may mean different things in some cultures, for instance in African-Caribbean societies hearing voices could be communication from ancestors

Escobar- The difference could be because British psychiatrists misinterpret symptoms in African- Caribbean people

Cultural bias- evaluations

The race of the psychiatrist- Trierwiler et al- looked at the diagnosis of 292 adults given by either African Americans or non- African Americans. They found that race did not play a significant part. However they did find that depending on the clinicians race they applied the diagnostic criteria differently. For instance Non- African Americans focused more on negative symptoms and African Americans on positive symptoms. This is an issue as social withdrawal could be a rational response to experiencing racism

Bias in the expression and interpretation of symptoms- Ryder and Chensova- Dutton- an over reliance on Western interpretations of symptom presentation can lead to misdiagnosis. For example affective flattening could be misdiagnosed in someone showing culturally restraint

Gender bias

The differential treatment or representation of people based on preset beliefs about their gender rather than any real difference

It is a problem because: it can lead to under or over diagnosis and incorrect treatment

Evidence- Fischer and Buchanan- since the 80s men have been diagnosed more than women (1.4:1)

Hoye et al- gave psychiatrists identical descriptions just changing the ‘he’ to a ‘she’. Psychiatrists in Norway and Russia were significantly more likely to diagnose the patient with SZ if they thought it was a man

Why is there so much over diagnosis- women are just less vulnerable

Cohen et al- they have closer relationships with people so better support

The classification system itself may have gender biased criteria

Gender bias - evaluations

Under recognition of SZ in women- Hoye et al found that in a Norweigan sample 33% of women received early diagnosis compared to 47% of men. This delay in diagnosis can have detrimental effects. Women were more likely to be told that they have a personality disorder

Its just PDD- symptoms of disorganised thoughts etc are dismissed as premenstrual dysphoric disorder- leading to women receiving medication for hormonal imbalances - Ganzalez- Rodriguez et al

Reliability

Consistency of diagnosis

An important measure of reliability is inter rater reliability- in relation to diagnosis this means that different clinicians make identical independent diagnosis of the same patient - Osario et al reported excellent reliability for the diagnosis of schizophrenia using the DSM 5 - 180 individuals were diagnosed and the inter rater reliability was +97

Another measure is test retest reliability and this is when the same clinician will reach the same diagnosis for the same patient at a different time

Osario et al reported excellent reliability for the diagnosis of schizophrenia using the DSM 5

180 individuals were diagnosed and the test retest reliability was +92

Reliability evaluation

Even if reliability of diagnosis based on classification systems is not perfect they do provide practitioners with a 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

Evidence does generally suggest that reliability of diagnoses has improved as classifications systems have been updated

Reliability is the consistency of diagnosis between classification systems however chaniaux et al had two psychiatrists independently diagnose 100 patients using both DSM and ICD criteria

DSM - 68 and ICD- 39

This poor reliability is a weakness of diagnosis of schizophrenia across classification systems questioning the validity of the criteria