Diagnosis Schizophrenia Flashcards
What are the two major systems for the classification of mental disorders?
The World Health Organisation’s, International Classification of Disease edition 10 (ICD-10) and the American DSM-5 (or DSM-V).
How do the ICD-10 and the DSM-5 differ in their classification of schizophrenia?
Eg. in the DSM-5 system one of the so-called positive symptoms - delusions, hallucinations or speech disorganisation - must be present for diagnosis whereas two or more negative symptoms are sufficient under ICD.
What are positive symptoms of schizophrenia?
These are additional experiences beyond those of ordinary existence eg. hallucinations and delusions
What are hallucinations? (Positive symptom)
These are unusual sensory experiences.
Some hallucinations are related to events in the environment whereas others bear no relationship to what the senses are picking up from the environment eg. voices heard either talking to or commenting on the sufferer.
The sufferer May see distorted facial expressions or occasionally people or animals that are not there.
What are delusions? (Positive symptom)
Delusions are irrational beliefs. These can take a range of forms.
Common delusions involve being an important historical, political or religious figure eg. Jesus or Napoleon.
Another class of delusions also involves the body; sufferers may believe that part of them is under external control.
What are negative symptoms?
They involve the loss of usual abilities and experiences eg. avolition and speech poverty
What is avolition? (Negative symptom)
Finding it difficult to begin or keep up with goal-directed activity i.e. actions performed in order to achieve a result.
Sufferers of schizophrenia often have a sharply reduced motivation to carry out a range of activities.
Andreason identified three identifying signs of avolition: poor hygiene and grooming, lack of persistence in work/education and lack of energy.
What is speech poverty? (Negative symptom)
Characterised by changes in pattern of speech.
ICD-10 recognises speech poverty as a negative symptom because the emphasis is on reduction in the amount and quality of speech in schizophrenia. This is sometimes accompanied by a delay in the sufferer’s verbal responses during conversation.
However, now the DSM system places its emphasis on speech disorganisation in which speech becomes incoherent or the speaker changes topic mid-sentence. This is classified in the DSM-5 as a positive symptom of schizophrenia, whilst speech poverty remains as a negative symptom.
What is co-morbidity?
The occurrence of two illnesses or conditions together, eg. a person has both schizophrenia and a personality disorder.
When two conditions are frequently diagnosed together it calls into question the validity of classifying the two disorders separately, because if they occur together a lot of the time then this calls into question the validity of their diagnosis and they might actually be a single condition.
What is symptom overlap?
Occurs when two or more conditions share symptoms. Where conditions share many symptoms this calls into question the validity of classifying the two disorders separately.
Eg. Both schizophrenia and bipolar disorder involve positive symptoms like delusions and negative symptoms like avolition.
This calls into question the validity of both classification and diagnosis of schizophrenia.
Under ICD a patient may be classified as a schizophrenic but the same patients may be classified with bipolar disorder according to DSM criteria-due to overlap of symptoms.
Weakness of diagnosis of schizophrenia: reliability
-an important measure of reliability is inter-rater reliability (the extent to which different assessors agree on their assessments).
In diagnosis, this means the extent to which two or more mental health professionals arrive at the same diagnosis for the same patients.
Elie et al. had 2 psychiatrists independently diagnose 100 patients using both DSM and ICD criteria.
Inter-rater reliability was poor, with one psychiatrist diagnosing 26 with schizophrenia according to DSM and 44 according to ICD, and the other diagnosing 13 according to DSM and 24 according to ICD.
This poor reliability is a weakness of diagnosis of schizophrenia.
What is a valid way of assessing the validity of a diagnosis?
Criterion validity: do different assessment systems arrived at the same diagnosis for the same patient?
After looking at Elis’ et al. figures, it’s clear that schizophrenia is more likely to be diagnosed using ICD and DSM. Poor validity.
Cultural bias in diagnosis:
Rates in Africa and West Indies are not as high as in the Western culture.
One issue of diagnosis is that 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
