A2 unit 4 Clinical Psychology 4) Content Reliability of the diagnosis of mental disorders Validity of the diagnosis of mental disorders Cultural issues
Pre-reading check • By now you should have read pages 234-245 (Brain) • You should be thinking about the use of the DSM and how reliable and valid it is, as well as the influence of cultural & gender issues in the diagnosis of mental disorders.
Learning outcomes: a) To be able to describe and evaluate the reliability of the diagnosis of mental disorders. b) To be able to describe and evaluate the validity of the diagnosis of mental disorders. c) To be able to describe and evaluate cultural issues in the diagnosis of mental disorders. (in all three cases using the findings of studies).
DSM- IV • The Diagnostic and Statistical Manual of Mental Disorder (Edition 5), was last published in 2013. • The DSM is produced by the American Psychiatric Association. • It is the most widely used diagnostic tool in psychiatric institutions around the world
ICD - 10 • There is also the International Statistical Classification of Diseases (known as ICD). • It is produced by the World Health Organisation (WHO) and is currently in it’s 10th edition.
Overview of DSM • Using hand out, highlight key points and complete table in pg5 in packs • Use text books if there is anything you are unsure about • Thought shower in your groups, strengths and weaknesses of the DSM
Evaluation of the DSM Strengths 1. Allows for common diagnosis (although many revisions) because it has stood the test of time When 2 or more doctors use the DSM, they should come close to the same diagnosis. 2. Evidence suggests that it is reliable ~Goldstein looked at the reliability between DSM-II and DSM-III is (1988) She found there was evidence of reliability within the DSM-III (but less so between DSM-II and DSM-III)
Evaluation of the DSM Weaknesses • The DSM is seen as a confirmation of the medical state of mental disorder, as suffers are ‘patients’ and ‘treatment’ is suggested. Mental health issues are ‘disorders’ and ‘illnesses’ so ‘cures’ are looked for. However, it might be said that some mental disorders are simply ways of living …. who is to say whether it is ‘illness’ or not. (e.g. schizophrenics may be trying to get back to their normal self)
Reliability and the diagnosis of mental disorders The DSM’s reliability rests on the question of whether one person’s set of symptoms would lead to a common diagnosis by different physicians If different doctors give different diagnosis for the same set of symptoms (e.g. for the same person), then the diagnosis are not reliable and the treatment may not work
Studies looking at the reliability of the DSM Goldstein (1988) • tested DMS-III for reliability and found that there was reliability • looked at the effect of gender on the experience of schizophrenia • she re-diagnosed 199 patients, originally diagnosed using DSM–II; some differences • she asked two other experts to re-diagnoses (single blind) a random sample of 8 of the patients using the case histories with all indication of previous diagnoses removed • high level of agreement/consistency of diagnosis
Goldstein (1988) • As she realised that she was aware of her hypothesis it was important that she asked two experts to re-diagnose a random sample of 8 patients. • She found a high level of agreement and inter-rater reliability. • This suggests that DSM-III is a reliable tool.
Other research exploring Reliability • Using text books, research other studies that have explored the reliability of the DSM • What have these studies shown? • look at the information about Kirk and Kutchin’s (1992) study…this is on the handout and on this PP which will be on the Blog
Kirk and Kutchins (K&K) (1992) • In their review paper Kirk and Kutchins argued that there are methodological problems with the studies used to test the reliability of the DSM up until 1992… these then limit the generalisability of the findings. • The studies outlined used interviews and questionnaires to gather data; K&K argued that training and supervision of interviews was insufficient and that they lacked the commitment and skills to be accurate. They also pointed out that the studies they looked at tended to take place in specialised research settings… meaning that their findings might not relate to clinicians in normal clinical settings. Generally speaking, an unreliable diagnostic tool would lack validity…. K&K suggested the DSM could also lack validity.
Evaluation of K&K (1992) points Points about interviewing - such as that different interviewers may affect the situation and lead to different data – might be important when considering generalising findings from studies Goldstein (1988) did not, however, use interviewing to test reliability – she used re-diagnosis using secondary data, and also found reliability
Evaluation of K&K (1992) points The patients in the studies looked at were not all from research settings The ‘gamblers’ in Stinchfield’s study were on a gambling treatment program, not in a research situation. The patients in Brown et al.’s study were out patients in a hospital = possible ecological validity?
Evaluation of K&K (1992) points • K&K’s study took place before Brown et al. and Stinchfield’s studies which showed that DSM-IV-TR could be regarded as reliable. Possible to therefore conclud that further work has been done since DSM-II and reliability has improved. • Goldstein (1988), Brown et al. (2003) and Stinchfield (2003) all provide evidence that diagnosis is reliable.
Questions: you also have questions in your pack ~ page 5 that need to be completed 1) What do these studies tell us about the reliability of the DSM in diagnosing mental disorders? 2) How are Kirk and Kutchin’s findings different from the majority of the other studies? What does this tell us about the reliability of the DSM? 3) How can the reliability of the DSM be improved?
Validity and the diagnosis of mental disorders • If the DSM were not reliable it would not be valid either. • If a diagnosis was done again and the DSM provided a different one, then it would not be a valid diagnosis (it would not be measuring what it claimed to measure) so therefore reliability and validity go together
Validity and the diagnosis of mental disorders Outline what is meant by each of the following terms: • Construct validity • Etiological validity • Concurrent validity • Predictive validity • Convergent validity
Construct validity • If the DSM is to define mental disorders, then mental disorders need to be operationalised. Lists of symptoms and behaviour are the result of making a mental disorder measurable. • It has been argued that in operationalising a concept such as depression, something is lost from the understanding of the nature of the whole experience of depression, which means that the DSM is not a valid tool. There is a lack of construct validity, in that the constructs drawn up, for example to represent depression, might not be representative enough.
Etiological validity If it has etiological validity, a group of people who have been diagnosed with the same disorder will have the same symptoms or factors causing it. e.g. schizophrenia is sometimes caused by too much of the neurotransmitter dopamine…. …..so in order to have etiological validity, people diagnosed as schizophrenic should all have an excess of dopamine in their brain
Concurrent validity • For a diagnosis to have concurrent validity, symptoms that form part of the disorder but are not part of the actual diagnosis, should be found in those diagnosed. e.g. schizophrenics often have problems with personal relationships, but this is not a characteristic that is looked at when diagnosing them according to the classification system.
Predictive validity • Predictive validity is present if diagnosis can lead to a prediction of future behaviours caused by the disorder. • If a diagnosis has predictive validity we should be able to say whether the person is likely to recover or whether the symptoms will continue • It should also be possible to predict how someone with a specific disorder will respond to specific treatments. e.g. the drug lithium carbonate is effective for bipolar disorder, but not effective for other mental disorders. If a classification system has good predictive validity and diagnoses someone with bipolar disorder, they should respond to lithium carbonate.
Convergent validity • Convergent validity is when a test results converges on (gets close to) another test result that measures the same thing. • A correlation test would be carried out ~ If two scales measure the same construct, for example, then a person’s score on one should converge with (correlate with) their score on the other.
Difference between convergent, predictive and concurrent • Convergent validity ~ the 2 measures should be measuring exactly the same thing • Predictive and concurrent can have different ways of measuring each case
Strengths – validity of diagnosis • Evidence that the DSM is valid in its diagnosis. • Different mental health issues cited in the different studies, which reinforces the conclusion • Likely that symptoms for disorders are well established, given that the DSM has had many revisions. • Different research methods have produced data that also match the DSM criteria.
Strengths – validity of diagnosis • Remember - if DSM is not reliable it will not be valid. • Great efforts have been made to make the DSM-IV-TR more valid, such as adding culture-bound syndromes. • What are culture-bound syndromes? • You already know 1!
Weaknesses – validity of diagnosis • co-morbidity – the state of having more than one mental disorder – is hard to diagnose using the DSM, • user chooses the one closest match from lists of symptoms and features • splitting a mental disorder into symptoms and features is reductionist and that a holistic approach might be more valid
Weaknesses – validity of diagnosis • Questionnaires and interviews produce the findings they are searching for • For instance, if it is well known that ‘children with ADHD are impulsive and hyperactive’, and teachers know which children have that label, they will then say, ‘those children are impulsive and hyperactive’. • The diagnosis is self-fulfilling
Culturalissues 2 ideas….. • Culture does not affect diagnosis – mental disorders are ‘scientific’ • The DSM was developed in the USA and is used widely in many other cultures. • It is valid if mental disorders are clearly defined with specific features and symptoms. • Mental disorders are scientifically defined illnesses that are explained in a scientific way.
Cultural issues • Culture does affect diagnosis – a spiritual model • studies have shown that culture can affect diagnosis • e.g. symptoms that are seen in western countries as characterising schizophrenia (such as hearing voices) are interpreted in other countries as showing possession by spirits, which is a positive ‘disorder’. • Depending on cultural interpretations of what is being measured, the DSM is not always valid. • A clinician from one culture must be aware that a patient from another culture is guided by their own frame of reference
Littlewood and Lipsedge (1997) • Littlewood & Lipsedge (1997) have suggested there is bias in the system, not a greater vulnerability in certain groups in society. • They describe the case of Calvin, a Jamaican man arrested for arguing with the police when a post-office clerk wrongly believed he was cashing a stolen postal order. After he was arrested the psychiatric report noted: “This man belongs to Rastafarian - a mystical Jamaican cult, the members of which think they are God-like. The man has ringlet hair, a straggly goatee beard and a type of turban. He appears eccentric in his appearance and very vague in answering questions. He is an irritable character and has got arrogant behaviour." As written by a British prison psychiatrist. • A psychiatrist must have knowledge of cultural factors before making a diagnosis e.g. in Puerto Rican culture believing that evil spirits can possess a person is a general belief, not schizophrenia! When testing a non-English speaker in English, the differences in language cause assumptions to be made.
Task … Using resources, complete page 8 -9 in your packs ~ skinny red and Brian are useful On the blog there is the Ford and Widiger study – this is looking at sex bias with diagnosis and worth a read to add to your research bank.