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Biomedical subjects

Graham Dunn

Publications and source records attributed to Graham Dunn.

48 records · Page 3Linked to original sources
PubMed2004

Why do people with delusions fail to choose more realistic explanations for their experiences? An empirical investigation.

Delusions can be viewed as explanations of experiences,. By definition, the experiences are insufficient to merit the delusional explanations. So why have delusions been accepted rather than more realistic explanations? The authors report a study of alternative explanations in 100 individuals with delusions. Patients were assessed on the following criteria: symptom measures, the evidence for the delusions, the availability of alternative explanations, reasoning, and self-esteem. Three quarters of the patients did not report any alternative explanation for the experiences on which the delusions were based. These patients reported significantly more internal anomalous experiences and had a more hasty reasoning style than patients who did have alternative explanations available. Having doubt in a delusion, without an alternative explanation, was associated with lower self-esteem. Clinicians will need to develop plausible and compelling alternative accounts of experience in interventions rather than merely challenge patients' delusional beliefs.

Adult↗
PubMed2004

Cognitive-behavioural therapy in first-episode and early schizophrenia. 18-month follow-up of a randomised controlled trial.

BACKGROUND: The initial phase of a trial of cognitive-behavioural therapy (CBT) for acutely ill patients with schizophrenia of recent onset showed that it speeded recovery. AIMS: To test the hypothesis that CBT in addition to treatment as usual (TAU) during the first or second acute episode of schizophrenia will confer clinical benefit over a follow-up period. METHOD: This was an 18-month follow-up of a multicentre prospective trial of CBT or supportive counselling administered as an adjunct to TAU, compared with TAU alone, for patients hospitalised for an acute episode of schizophrenia of recent onset. Primary outcomes were total and positive symptom scales, time to relapse and re-hospitalisation. RESULTS: There were significant advantages for CBT and supportive counselling over TAU alone on symptom measures at 18 months but no group difference was seen for relapse or re-hospitalisation. There was a significant centre-treatment interaction, reflecting centre differences in the effect of introducing either treatment, but not in the comparison of CBT and supportive counselling. Medication dosage and compliance did not explain group differences. CONCLUSIONS: Adjunctive psychological treatments can have a beneficial long-term effect on symptom reduction.

Acute Disease↗
PubMed2003

The evolution of symptoms in the early course of non-affective psychosis.

Most previous studies investigating the factor structure of psychosis have focussed on chronic samples. First episode samples with longitudinal follow up are few. To investigate the stability and validity of symptom factors, a sample of 257 patients with DSM IV nonaffective psychoses were assessed using the PANSS during the acute first episode and at 3- and 18-month follow up. Exploratory factor analysis of the changes in PANSS item scores over time gave a five-factor solution. This was consistent with the solutions to factor analyses at the initial assessment and each of the follow-ups. However, there was progression over follow-up. Confirmatory factor analysis demonstrated that symptom ratings at 18-month follow-up fitted the models from existing research, in relatively chronic samples, better than the ratings at the initial assessment. A psychomotor poverty factor showed most stability over time and a positive symptom factor most change. Factors showed different associations with demographic and external variables, further supporting their validity.

Acute Disease↗
PubMed2003

Comparison of thermography and laser Doppler imaging in the assessment of Raynaud's phenomenon.

The main objective of the study was to compare the techniques of thermographic and laser Doppler imaging in the assessment of digital blood flow. Thermography measures surface temperature; laser Doppler measures microciculatory flow. Seventeen healthy control subjects and 40 patients with Raynaud's phenomenon (7 primary, 33 secondary to systemic sclerosis) underwent a 20-min acclimatization period at 23 degrees C. Thermographic and then laser Doppler images were taken of the dorsal aspect of both hands, and the procedure was repeated at a room temperature of 30 degrees C. Three regions/values of interest from each hand were chosen for analysis: the dorsum of the hand, the tip of the middle finger, and the "gradient" between these. Thermographic and laser Doppler results correlated poorly. For example, correlations between techniques for the gradient value were as follows: left hand 23 degrees C, r = 0.61; right hand 23 degrees C, r = 0.64; left hand 30 degrees C, r = 0.47; right hand 30 degrees C, r = 0.48. One explanation for these findings is that laser Doppler imaging is more sensitive to blood flow changes and therefore more likely to show inhomogeneities than the highly damped temperature response. Therefore one technique cannot substitute for another.

Blood Flow Velocity↗
PubMed2003

Describing, explaining or predicting mental health care costs: a guide to regression models. Methodological review.

BACKGROUND: Analysis of the patterns of variation in health care costs and the determinants of these costs (including treatment differences) is an increasingly important aspect of research into the performance of mental health services. AIMS: To encourage both investigators of the variation in health care costs and the consumers of their investigations to think more critically about the precise aims of these investigations and the choice of statistical methods appropriate to achieve them. METHOD: We briefly describe examples of regression models that might be of use in the prediction of mental health costs and how one might choose which one to use for a particular research project. CONCLUSIONS: If the investigators are primarily interested in explanatory mechanisms then they should seriously consider generalised linear models (but with careful attention being paid to the appropriate error distribution). Further insight is likely to be gained through the use of two-part models. For prediction we recommend regression on raw costs using ordinary least-square methods. Whatever method is used, investigators should consider how robust their methods might be to incorrect distributional assumptions (particularly in small samples) and they should not automatically assume that methods such as bootstrapping will allow them to ignore these problems.

Cost-Benefit Analysis↗
PubMed2003

Mental health of Kosovan Albanian refugees in the UK.

BACKGROUND: In 1999 the UK received 4346 refugees from Kosovo. AIMS: To determine the prevalence of mental health problems in this group. METHOD: A sample of 842 adults was surveyed. All were asked to complete self-report questionnaires (translated into Kosovan Albanian). A subset of 120 participants were later interviewed in Albanian using the Clinician Administered PTSD (post-traumatic stress disorder) Scale and a depression interview. RESULTS: The study yielded estimates of prevalence of PTSD and depression. Self-report measures appear to overestimate the prevalence of these disorders. Just under half of the group surveyed had a diagnosis of PTSD and less than one-fifth had a major depressive disorder. CONCLUSIONS: These results may be taken as a sign of the resilience of many who survived this conflict but they also imply that there is still a substantial need for good health and social care in a significant proportion. Psychosocial interventions are likely to be an important part of the treatment programme.

Adult↗
PubMed2002

Aortic pulse-wave velocity and its relationship to mortality in diabetes and glucose intolerance: an integrated index of vascular function?

BACKGROUND: Arterial distensibility measures, generally from pulse-wave velocity (PWV), are widely used with little knowledge of relationships to patient outcome. We tested whether aortic PWV predicts cardiovascular and all-cause mortality in type 2 diabetes and glucose-tolerance-tested (GTT) multiethnic population samples. METHODS AND RESULTS: Participants were randomly sampled from (1) a type 2 diabetes outpatient clinic and (2) primary care population registers, from which nondiabetic control subjects were given a GTT. Brachial blood pressures and Doppler-derived aortic PWV were measured. Mortality data over 10 years' follow-up were obtained. At any level of systolic blood pressure (SBP), aortic PWV was greater in subjects with diabetes than in controls. Mortality risk doubled in subjects with diabetes (hazard ratio 2.34, 95% CI 1.5 to 3.74) and in those with glucose intolerance (2.12, 95% CI 1.11 to 4.0) compared with controls. For all groups combined, age, sex, and SBP predicted mortality; the addition of PWV independently predicted all-cause and cardiovascular mortality (hazard ratio 1.08, 95% CI 1.03 to 1.14 for each 1 m/s increase) but displaced SBP. Glucose tolerance status and smoking were other independent contributors, with African-Caribbeans experiencing reduced mortality risk (hazard ratio 0.41, 95% CI 0.25 to 0.69). CONCLUSIONS: Aortic PWV is a powerful independent predictor of mortality in both diabetes and GTT population samples. In displacing SBP as a prognostic factor, aortic PWV is probably further along the causal pathway for arterial disease and may represent a useful integrated index of vascular status and hence cardiovascular risk.

Aorta↗
PubMed2002

An epidemiologic study of trends in prevalence of rheumatoid factor seropositivity in Pima Indians: evidence of a decline due to both secular and birth-cohort influences.

OBJECTIVE: Previous population studies have suggested that both rheumatoid factor (RF) production and rheumatoid arthritis (RA) may be declining in occurrence, and both secular and birth-cohort influences have been implicated. Since Pima Indians have a very high incidence of RA and also have shown recent evidence of a decline in RA, this study evaluated the relative contributions of age, secular, and birth-cohort influences on RF seropositivity in the Pima Indian population. METHODS: RF data, as assayed by both the bentonite flocculation test (BFT) and the sheep cell agglutination test (SCAT), were available on 5,345 Pima Indians born between 1886 and 1975, who were surveyed at biennial intervals between 1966 and 1995. An age-period-cohort analysis was conducted using data on 18,295 examinations undertaken during the period of study. RESULTS: There was a decline in the proportion of positive test results for RF (titer > or = 1:32) by both BFT and SCAT, in both male and female subjects from 1966-1975 to the later decades of the study (1976-1985 and 1986-1995). Across all periods, by both assays, the crude proportion of positive titers increased with increasing age of the subjects. There was a very clear birth-cohort effect: the highest likelihood of seropositivity was in those individuals born around the end of the nineteenth century, with continuing decline in seropositivity up to the most recent birth cohort. A logistic regression analysis, adjusting for Pima heritage and sex, demonstrated a substantially greater influence of birth cohort than of calendar year on the frequency of RF positivity. CONCLUSION: In the Pima Indian population, environmental influences in early life are important predictors of the lifelong likelihood of RF positivity. This may have implications for understanding the epidemiology and etiology of RA.

Adolescent↗
PubMed2002

Prevalence and risk factors for depression in a rural setting. Results from the North Wales arm of the ODIN project.

BACKGROUND: Depressive disorders are common, and result in high individual and societal costs. The majority of research assessing depression has occurred in urban areas. There is a paucity of research examining the prevalence of and risk factors for depression in rural general practice. AIM: The aim of this study was to examine the prevalence of and risk factors for depression in a rural area of North Wales in the context of a large multi-centre European study. METHOD: One thousand nine hundred and ninety-nine people randomly selected from a health authority database underwent a two-phase screening method to identify depression. The first phase involved patients completing a self-rating postal questionnaire (the Beck Depression Inventory or BDI). In the second phase, those scoring above cut-off underwent detailed diagnostic interview (Schedules of Clinical Assessment in Neuropsychiatry or SCAN). The SCAN diagnostic interview can generate either DSM-IV or ICD-10 diagnoses; the DSM-IV classification system was used here. RESULTS: One thousand two hundred and thirty-nine (63 %) people responded to the initial screening questionnaire. The prevalence rate for all DSM-IV depressive disorders was calculated to be 6.1 % (95 % CI 4.1, 9.0) whereas the prevalence rate for DSM-IV major depressive disorder was 5.1 % (CI 3.37, 7.66). Multivariate analysis indicated that several variables were related to BDI caseness, including gender, employment status, social support and negative life events. CONCLUSION: Levels of reported depression are relatively low in North Wales compared to those observed in a neighbouring urban area using comparable data collection methods. A number of factors traditionally associated with increased risk from depression were predictive of scoring above cut-off on the BDI in a rural North Wales sample.

Adult↗
PubMedDate not supplied

Turning theory into practice: rationale, feasibility and external validity of an exploratory randomized controlled trial of training family practitioners in reattribution to manage patients with medically unexplained symptoms (the MUST).

BACKGROUND: The evidence for the effectiveness of reattribution training are limited, and optimal service delivery is not yet established. OBJECTIVES: The objectives of this study were to establish the feasibility and to optimize the service delivery and design of a definitive randomized controlled trial (RCT) of reattribution training for patients with medically unexplained symptoms (MUSs) in routine primary care. METHODOLOGY: The study was of a cluster RCT design with the practice as the unit of randomization. Health facilitator (HF)-delivered reattribution training was compared with no reattribution training. The primary outcome measure used is doctor-patient communication in the consultation. Quantitative and qualitative methods identify barriers to effectiveness. The acceptability and feasibility of the intervention were established by attendance rates and postal survey after completion of training. RESULTS: Sixteen practices and 70 family practitioners (FPs) were recruited with representative practice and FP characteristics. Six hours of HF reattribution training to FPs in the workplace proved feasible and acceptable with all 35 FPs completing the training. Feedback from 27 (77%) FPs who received training indicated that 25 (93%) FPs believed that specific and relevant learning achievements were made, 22 (82%) felt more confident and 21 (77%) thought the training was useful. CONCLUSION: HF-delivered reattribution training to whole practices is feasible and acceptable, and its effectiveness is measurable in routine primary care.

Adult↗
PubMedDate not supplied

Estimating the causal effects of treatment.

OBJECTIVE: To provide a relatively non-technical review of recent statistical research on the analysis and interpretation of the results of randomised controlled trials in which there are possibly all three of the following types of protocol violation: non-adherence to allocated treatment, contamination (that is, patients receiving treatments other than the one to which they were allocated) and attrition (missing outcome data). METHODS: The estimation methods involve the use of potential outcomes (counterfactuals) in the definition of a causal effect of treatment and in drawing valid inferences concerning its size. RESULTS: The methods are explained through the use of simple arithmetical expressions involving the counts from three-way contingency tables (Outcome by Treatment Received by Random Allocation). Illustration is provided through the use of a hypothetical data set. CONCLUSIONS: Recent advances in statistical methodology enable one to estimate treatment effects from the results of randomized trials in which the treatment actually received is not necessarily the one to which the patient was allocated. These methods allow one to make adjustments to allow for both non-compliance and loss to follow-up. Even for such a 'broken' randomised trial, inference concerning causal effects is safer than that from data arising from an observational study that never involved random allocation in the first place.

Humans↗