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Clinical psychology Definition of the application
? Clinical psychology is the study of mental health and well-being and includes the study of mental health conditions and disorders.
? Clinical psychology aims to classify and diagnose, explain and treat mental health conditions or disorders, to reduce psychological distress and enhance and promote psychological well-being.
? Clinical psychologist work in a range of settings including hospitals, health centres, community mental health teams, child and adolescent mental health services (CAMHS) and social services. They work with children and adults with mental and physical health problems, including anxiety, depression, relationship problems and addictions.
? They undertake clinical needs assessments using psychometric tests, interviews and direct observations of behaviour. They deliver and evaluate the effectiveness of therapy, counselling and advice.
? Clinical psychologists often work as part of a team with, social workers, medical practitioners and other health professionals. Most of them work for the National Health Service, which has clearly defined career structure, but some work in private practice.
? The work is often directly with people, both individually or in groups, assessing their needs and providing therapies based on psychological theories and research. Some clinical psychologists also work as trainers, teachers and researchers at universities.
How science works Primary and secondary data Primary data
? Collected first hand by the researcher for a specific research purpose. It can be qualitative or quantitative.
? An example of qualitative primary data is Brown et al. 1986 who interviews pps and information was collected about self-esteem, life events and perceived social support over the course of the longitudinal study.
? An example of quantitative primary data was encountered in Castner et al. (1998) where a study of rhesus monkeys later exposed whilst in the uterus to radiation to see whether this led to symptoms of schizophrenia later in life; here the monkeys were observed for signs of hallucinations (a nominal scoring system was used such as a tally chart).
? The monkeys were also given cognitive tests to see whether exposure to radiation led to disordered thinking. These tests would have led to ratio data in the form of scores on a standardised psychological tests and this is also a form of primary data collection. Secondary data
? This means that someone else has already collected the information, for a different purpose and the information have been stored on record for use by other researchers. The researcher will re-analyse this second hand data for a new purpose.
? Results of psychological studies are classed as secondary data and often a researcher will conduct an in-depth review of the data in the area of interest before embarking on his or her own primary data collection.
? In clinical psychology, secondary data might include medical records made by doctors including diagnosis of disorders or how a patient has responded to treatment options. It could also include school reports which provide insight into an individual's life before the onset of a disorder.
? A specific example of the use of secondary data in clinical psychology was Gottesman and Shields (1966) use of pre-existing diagnoses of schizophrenia and other psychiatric disorders in their twin pairs from Bethlem and Maudsley hospital. Using both types of data Gottesman and Shields (1966) used both types of data in their study to see if schizophrenia is inherited. First, they found out the mental health of pairs of identical and non-identical twins by accessing hospital records for twin where at least one of the pair had been diagnosed with a mental disorder. This was using secondary data. They then interviewed the twins, as adults, to assess their mental health and to find out the course of their mental disorder. When interviewing they were gathering primary data. They gathered quite a lot of information about the twins and then drew conclusions about how often when at least one twin had schizophrenia or some related disorder; the other had been diagnosed with it as well. Evaluation of primary and secondary data Primary strengths
? Gathered of intended purpose therefor likely to be more focused on that purpose, secondary data taken from another source and have often been gathered for a different reason. E.g. Gottesman and shields (1966) had to discount some of their pairs of twins because they could not be sure whether they were monozygotic or dizygotic twins, which affected their study.
? Primary data tends to be more valid in that they are gathered first hand and any operationalizing is done carefully with the purpose in mind so the data are more likely to represent real life. Secondary data if they are statistics from surveys, which they often are might not be valid if used as if they are about individuals. However if the secondary data was originally primary data from another study, then they might well have been gathered validly.
? Primary data is more likely to have credibility as they are gathered for a specific purpose and analysed with that purpose in mind. Secondary data are likely to have been gathered with one purpose in mind and when used in a 'secondary' fashion they may not be seen to have credibility.
? Primary data are analysed directly by the researchers, whereas secondary data may already have been analysed, which can bring in an element of subjectivity. However, secondary data can be 'raw' data and not previously analysed.
? Primary data are gathered at the time of the study, whereas secondary data is likely to be gathered some time previously, which mean primary data are more likely to be valid in the sense of being up to date. Secondary strengths
? Secondary data are cheaper because they are already there. Primary data tend to be expensive because the study has to be run completely, including finding the pps, developing the research method and setting up any situation or survey.
? Secondary data can involve more pps, such as in meta-analysis, so the range of pps can be wider and generalizability can be improved. This is not always the case but in studies such as craft et al. (2003), where they used data from many
studies that used the same questionnaire, they had a lot more data than if they gathered the information first hand. Studies gathering primary data are often limited in the number if people they involve.
? Secondary data tends to consist of more data too, although again this is not always the case. E.g. Gottesman and Shield (1966). By using the hospital records over a number of years were able to access a lot of detail about pairs of twins that otherwise would have been hard, if not impossible, to put together p. when gathering primary data it is often the case that the numbers that can be involved are limited, either by cost or to make the study manageable, or both. Reliability and validity Reliability
? Reliability refers to the consistency with which a measure of psychological variable identifies the same thing.
? A diagnosis of mental disorder is considered reliable if more than one psychologist gives the same diagnosis to the same Individuals, therefore the diagnosis is consistent. This is known as inter-rather reliability.
? For example, in Rosenhan's (1973) each of the pseudo patients reported the exact same symptoms and in 7 out of 8 cases, the same diagnosis was applied, (schizophrenia) suggesting reliability, if not validity in diagnosis.
? Reliability can also be assessed by seeing whether the same individual is given the same diagnosis when assessed at several intervals. This is called test-retest reliability.
? This is often measured using PPVs (positive predictive value) which is basically a percentage which tells us the percentage of people who keep the same diagnosis over time.
? Cohen's kappa in another figure used when talking about reliability of diagnosis; this is a decimal which again shows the proportion of people who keep the same diagnosis. Validity
? Validity refers to the extent to which a measure of a psychological variable measures what it sets out to measure and that the measurement is not simply a reflection of the testing situation but of the persons behaviour, thinking and emotions more generally, in their everyday life.
? With regard to the diagnosis of mental disorders, the DSM IV TR and other diagnostic systems such as the ICD 10 operationalize mental disorders using lists of symptoms, however some psychologists feel that these lists do not have construct validity; that when symptoms are similar across different disorders, then validity of diagnosis is limited in It is possible that the distinctions made between disorders are false.
? Secondly psychologists argue about the predictive validity of the various diagnoses; if a person is given a certain diagnosis, then this should successfully predict that they will experience relief if given a known treatment for this particular disorder and that people given this diagnosis will respond to the treatments in similar ways.
? Finally a diagnosis can be said to have concurrent validity if the individual is assessed using two or more different techniques and the same disorder is identifies using each technique, for example self-rating, family or teacher observations and psychological testing. Definition of schizophrenia
? Schizophrenia is a psychotic condition that affects approximately 1% of people at some point in their lives worldwide
? It affects the same number of males and females but the age of onset is earlier for males
? The condition is more common in those from lower social economic backgrounds and those living in urban as opposed to rural communities
? This condition will only be diagnosed if symptoms have been present for at least six months
? Symptoms include disturbances to a person's thoughts, emotions and behaviours that can lead the the person withdrawing from social life and becoming unable to function
? The condition includes positive and negative symptoms; positive symptoms include hallucinations, delusions, disorganised language and motor behaviour while negative symptoms include affective flattening, alogia (lack of speech and avolition (lack of purposeful behaviour) Using twin studies to research schizophrenia One way of finding out whether a disorder has a genetic component is to see whether it runs in families. If relatives of sufferers have a higher than average risk of getting the disorder themselves, then it may be that the disorder has a genetic component. However, family members typically share similar environments. Consequently, increased risk amongst close relative may simply indicate that that are exposed to the same set of environmental risks. An alternative approach is to do a twin study. This looks at the concordance rate (degree of similarity) of twins with respect to the disorder being considered. Concordance rates means the probability of one twin having the disorder if the other already has it expressed as a percentage. In a twin study, MZ (identical) and DZ (non-identical) twins are compared. Whilst MZ twins have a greater degree of genetic similarity, both types of twin pair grow up in identical environments. So if we discover that MZ twins have a higher concordance, this cannot be because their environments are more similar than those of DZ twins; it must therefore be because their genes are more similar. When interpreting twin study data, we look for the following features: Feature
MZ concordance is significantly higher than DZ concordance
The disorder has a genetic component
MZ concordance is same or similar to DZ concordance
The disorder is environmentally caused.
MZ concordance is 100%
MZ concordance is significantly less than 100%
The disorder is genetically caused The disorder has an environmental component
Strengths of twin studies
? Twins provide a perfect way of controlling for genetic inheritance as MZs always share 100% and DZ share 50%, a naturally occurring manipulation of an independent variable, yet both have the same environmental experience (control of confounding variables) meaning that the effect of nature over nurture can be studied effectively.
? With increasing numbers of multiple births, it is possible to replicate the findings of twin studies with large samples in many different world cultures, increasing the reliability and generalisability of the findings; records of multiple births means that researchers can easily find large sample with which to test their hypotheses
Weaknesses of twin studies
? One of the grounding assumptions of the twin study methodology concerns the degree of similarity between the environments of MZ and DZ twins. Because both types of twin pair are born at the same time into the same environment it is assumed that each member of a twin pair is exposed to exactly the same set of environmental influences, regardless of zygosity. However, this not strictly true as ...
? MZ twins can experience differences in terms of environmental experiences, even in the womb
? MZ twins are typically closer than DZ twins, their parents are more likely to dress them similarly and they are always the same sex; all these factors mean that people will treat them more similarly and therefore it may not be right to assume that both MZ and DZ twin pair share equally similar environments; MZ environments may be more similar than DZs
? Even though genetically identical, MZ twins are not exactly the same; their fingerprints are different. One twin is typically larger and more robust than the other; first observable in his difference is first observable during pre-natal development.
? Genes turn on and off at different point in life and in interaction with differing environmental experiences (epigenetic modification); therefore MZ twins may both share a gene or cluster of genes which predispose them to schizophrenia however, only one twin may be exposed to the environmental circumstances which trigger that gene to start affecting the person's thinking and behaviour (cross reference to nature-nurture debate)
? The validity of the findings of twin studies still rely on the validity and reliability of the measures used to ascertain the degree of similarity on the certain characteristic in question, in this case schizophrenia; and it is possible that systems such as the DSM are only valid for certain sub-types of schizophrenia
? In studies of separated twins, whereby similarity in developmental outcomes must be due to genes and not to similar environments are problematic as often
the environments that they are placed in are actually more similar than the researches have credited
? Genetic inheritance in schizophrenia may be a more complex issue than twin studies would at first have us believe; Boklage (1977)noted that if MZ twins were both right handed, the concordance rate for schizophrenia was 92% but if one was right handed and the other left-handed, the concordance rate was only 25%!
Example of a twin study: Gottesman and Shields (1966) Aim
? To explore the extent to which schizophrenia is a heritable condition, i.e. genetic by comparing the concordance rates between MZ and DZ twin pairs where one of the twins already had a diagnosis of schizophrenia
? To replicate findings of previous research that had suggested that this was the case.
? To explore the extent to which siblings of individuals with schizophrenia suffer from other psychiatric disorders or at least form some psychological abnormality, and to see whether this varies between MZ and DZ twin pairs Procedure Collection of secondary data:
? Hospital records for 16 consecutive years of admissions to the Maudsley and Bethlem Royal Joint Hospital were examined and out of approx 45000 patients in total, there had been 392 patients who said they were same-sex twins; of these patients, 47 had been diagnosed with schizophrenia (born between 1893 and 1945)
? The researchers also identified several more twin pairs, where the patients had left the hospital but subsequently been diagnosed with schizophrenia
? In the end they had a sample of o 52 pairs of twin where one twin was a member of the sample and 5 additional pairs where both twins were members of the sample (i.e. they both had schizophrenia), thus
57pairs represented in the sample, 24 MZ pairs and 33 DZ pairs
o 62 individual participating twins; o 31 male and 31 female; aged between 19-64, mean average 37 o There were 6 additional twin pairs who were not allowed to be in the sample; 3 were from overseas which might have invalidated the diagnoses of schizophrenia, and three more had unclear diagnosis of zygocity (MZ /DZ status)
? Further secondary data was collected using the hospital records of the twins to
find out about their case histories and identify references to diagnoses of schizophrenia Collection of primary data
? More data was collected by the researchers themselves using semi-structured interviews from which verbal behavior could be analyzed, personality test and tests of thought disorder. Validity of MZ/DZ diagnosis: Blood tests, fingerprint analysis, assessment of physical resemblance Collection Results The researchers analyzed the concordance rates relating to four potential outcomes,
? Both twins have schizophrenia
? one twin has schizophrenia and the other has another psychiatric diagnosis
? one twin has schizophrenia and the other has some psychiatric abnormality picked up within the researchers' own primary data collection
? one twin has schizophrenia yet the other has no detectable mental health problems, i.e. normal Grade Both schizophrenic Co-twin either schizophrenic or has another clinical disorder Co-twin either schizophrenic, has another clinical disorder or is psychiatrically abnormal One twin has schizophrenia and the other is 'normal'
%) 42 54
) 9 18
In addition the researchers found a gender difference in that the concordance rates were slightly higher for females compared with males, however, the samples sizes were very small and so this findings may not be reliable They also found that in the most severe cases of schizophrenia, the concordance rate was much higher, between 75% and 91% in MZs but only 22% for DZs. Conclusion Genes appear to play an important role in schizophrenia because the concordance rate is higher in MZ twins than DZ twins. However environmental factors must also be important; Gottesman and Shields (1966) support a diathesis-stress model of schizophrenia where by a predisposition is inherited but is only triggered under certain environmental circumstances; individuals may inherit.
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