Reliability and Validity in the Diagnosis and Classification of Scizophrenia Flashcards
In the context of the diagnosis of schizophrenia, what does reliability refer to?
the consistency of measuring the symptoms of schizophrenia
How can reliability be assessed? (AO1)
Test-retest reliability is the extent to which a clinician makes the same diagnosis of schizophrenia on separate ocasions from the same information provided by the patient.
• Inter-rater reliability- the extent to which different clinicians independently make the same diagnosis of schizophrenia, for the same patient.
What are the issues that affect the reliability of the diagnosis of schizophrenia?
-Culture bias and Symptom overlap
What is culture bias?
-concerns differential treatment towards ethnic groups.
-there is tendency for members of certain ethnic minorities to be over-diagnosed with schizophrenia )e.g. people of Afro-Caribbean descent are several times more likely than white people to be diagnosed- could be because the people who create diagnostic tools such as the DSM are from predominately white backgrounds, with a different set of norms and values to other ethnic groups. (base on their society)
How can cultural bias therefore affect inter-rather reliability of diagnosis and classification?
because an individual reporting the same symptoms to clinicians from different cultural backgrounds may not receive the same diagnosis
What is symptom overlap?
-occurs when the characteristics of a particular disorder are shared with another.
e.g. schizophrenia and bipolar disorder are often characterised by the common symptom of depressed mood.
Why can symptom overlap affect the inter-rater reliability of diagnosis?
because if a person presents the symptom of depressed mood to different clinicians, one may provide a diagnosis of schizophrenia and bipolar disorder (issue as both have different treatments - can’t treat bipolar with antipsychotics, can’t treat schizophrenia with antidepressants)
In the context of the diagnosis of schizophrenia, what is validity?
validity concerns the accuracy of measuring symptoms and whether classification systems can distinguish schizophrenia form other disorders. (how sure is the clinician)
What are the two ways the validity of a diagnosis of schizophrenia can be assessed?
-Concurrent Validity
-Predictive Validity
What is concurrent validity?
-the extent to which different classification systems identify symptoms of schizophrenia according to their criteria and the systems arrive at the sane diagnosis of schizophrenia
-If both systems agree, the diagnosis has concurrent validity.
What is predictive validity?
-the extent to which a diagnosis of schizophrenia leads to a treatment which is successful in reducing a patient’s symptoms.
-If the treatment outcome is successful, the diagnosis has/predictive validity
What are two issues that affect the validity of diagnosis of schizophrenia?
-Co-Morbidity
-Gender Bias
What is co-morbidity?
occurs when a person has two or more disorders at the same time.
e.g. schizophrenia is often co-morbid
disorders such as substance abuse, depression and OCD.
How can co-morbidity affect the validity of classification and diagnosis of schizophrenia?
because it leads to uncertainty about whether such different disorders can be considered independently or not.
e.g. schizophrenia may not always be a separate disorder to depression; depression may be a symptom of schizophrenia and therefore occur at the same time.
What is gender bias?
-refers to differential treatment or representation of males and females, based on stereotypes.
-In the context of diagnosing schizophrenia, males are statistically more likely to be diagnosed than females.
-However, this may misrepresent the true prevalence of the disorder for each sex.
-For instance, female patients typically function better than males when suffering with symptoms such avolition, so may cope or seek support from others.
