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Biomedical subjects

S Wessely

Publications and source records attributed to S Wessely.

At least 55 records · Page 3Linked to original sources
PubMed2001

Prevalence of Gulf war veterans who believe they have Gulf war syndrome: questionnaire study.

OBJECTIVES: To determine how many veterans in a random sample of British veterans who served in the Gulf war believe they have "Gulf war syndrome," to examine factors associated with the presence of this belief, and to compare the health status of those who believe they have Gulf war syndrome with those who do not. DESIGN: Questionnaire study asking British Gulf war veterans whether they believe they have Gulf war syndrome and about symptoms, fatigue, psychological distress, post-traumatic stress, physical functioning, and their perception of health. PARTICIPANTS: 2961 respondents to questionnaires sent out to a random sample of 4250 Gulf war veterans (69.7%). MAIN OUTCOME MEASURE: The proportion of veterans who believe they have Gulf war syndrome. RESULTS: Overall, 17.3% (95% confidence interval 15.9 to 18.7) of the respondents believed they had Gulf war syndrome. The belief was associated with the veteran having poor health, not serving in the army when responding to the questionnaire, and having received a high number of vaccinations before deployment to the Gulf. The strongest association was knowing another person who also thought they had Gulf war syndrome. CONCLUSIONS: Substantial numbers of British Gulf war veterans believe they have Gulf war syndrome, which is associated with psychological distress, a high number of symptoms, and some reduction in activity levels. A combination of biological, psychological, and sociological factors are associated with the belief, and these factors should be addressed in clinical practice.

Adult↗
PubMed2001

Direct observation of hole transfer through DNA by hopping between adenine bases and by tunnelling.

The function of DNA during oxidative stress and its suitability as a potential building block for molecular devices depend on long-distance transfer of electrons and holes through the molecule, yet many conflicting measurements of the efficiency of this process have been reported. It is accepted that charges are transported over long distances through a multistep hopping reaction; this 'G-hopping' involves positive charges moving between guanines (Gs), the DNA bases with the lowest ionization potential. But the mechanism fails to explain the persistence of efficient charge transfer when the guanine sites are distant, where transfer rates do not, as expected, decrease rapidly with transfer distance. Here we show experimentally that the rate of charge transfer between two guanine bases decreases with increasing separation only if the guanines are separated by no more than three base pairs; if more bridging base pairs are present, the transfer rates exhibit only a weak distance dependence. We attribute this distinct change in the distance dependence of the rate of charge transfer through DNA to a shift from coherent superexchange charge transfer (tunnelling) at short distances to a process mediated by thermally induced hopping of charges between adenine bases (A-hopping) at long distances. Our results confirm theoretical predictions of this behaviour, emphasizing that seemingly contradictory observations of a strong as well as a weak influence of distance on DNA charge transfer are readily explained by a change in the transfer mechanism.

Adenine↗
PubMed2001

Chronic fatigue: symptom and syndrome.

Chronic fatigue is common, is difficult to measure, can be associated with considerable morbidity, and is rarely a subject of controversy. The chronic fatigue syndrome also presents problems in definition and measurement, is associated with even more morbidity than chronic fatigue itself, and is often controversial. Particularly unclear is the way in which chronic fatigue and the chronic fatigue syndrome relate to each other: Is one the severe form of the other, or are they qualitatively and quantitatively different? We know that many things can cause chronic fatigue, and this is probably true for the chronic fatigue syndrome, too. We can anticipate that discrete causes of the chronic fatigue syndrome will be found in the future, even if these causes are unlikely to fall neatly along the physical-psychological divide that some expect. The causes of chronic fatigue are undoubtedly many, both in a population and in any individual person, even when a discrete cause, such as depression or cancer, is identified. Social, behavioral, and psychological variables are important in both chronic fatigue and the chronic fatigue syndrome. Interventions that address these general variables can be successful, and currently they are often more successful than interventions directed at specific causes.

Chronic Disease↗
PubMed2001

Medically unexplained symptoms in frequent attenders of secondary health care: retrospective cohort study.

OBJECTIVE: To estimate the prevalence of medically unexplained symptoms in patients who most frequently attend outpatient services. DESIGN: Retrospective cohort study over three years with review of case notes. SETTING: Secondary care services in the South Thames (West) NHS region. PARTICIPANTS: Outpatient attenders with new appointments in 1993. MAIN OUTCOME MEASURES: Number of outpatient appointments, and number of consultation episodes for medically unexplained conditions. RESULTS: Medical records of 361 of 400 sampled frequent attenders were examined, and 971 consultation episodes were recorded. Ninety seven (27%) had one or more consultation episodes in which the condition was medically unexplained; 208 (21%) of the 971 consultation episodes were medically unexplained. Abdominal pain, chest pain, headache, and back pain were commonly found to be medically unexplained. CONCLUSIONS: Medically unexplained symptoms present in most hospital specialties and account for a considerable proportion of consultations by frequent attenders in secondary care.

Abdominal Pain↗
PubMed2001

Multiple chemical sensitivity and chronic fatigue syndrome in British Gulf War veterans.

The objective of this study was to measure the prevalence of multiple chemical sensitivity (MCS) and chronic fatigue syndrome (CFS) in British Gulf War veterans and to investigate their association with reported exposures and psychologic morbidity. In 1997--1998, the authors undertook a cross-sectional survey of three cohorts of British military personnel comprising Gulf veterans (n = 3,531), those who had served in Bosnia (n = 2,050), and those serving during the Gulf War but not deployed there (Era cohort, n = 2,614). MCS and CFS were defined according to operational criteria. The prevalence of MCS in the Gulf, Bosnia, and Era cohorts was 1.3%, 0.3%, and 0.2%, respectively. For CFS, the prevalence was 2.1% (Gulf cohort), 0.7% (Bosnia cohort), and 1.8% (Era cohort). In Gulf veterans, MCS was strongly associated with exposure to pesticides (adjusted odds ratio = 12.3, 95% confidence interval: 5.1, 30.0). Both syndromes were associated with high levels of psychologic morbidity. These findings suggest that CFS and MCS account for some of the medically unexplained illnesses reported by veterans after deployment to the Gulf. MCS was particularly associated with Gulf deployment and self-reported exposure to pesticides, findings that merit further exploration given the controversial status of this diagnosis and the potential for recall bias in a questionnaire survey.

Adult↗
PubMed2001

Antidepressants using active placebos.

BACKGROUND: Although there is a consensus that antidepressants are effective in depression, placebo effects are also thought to be substantial. Side effects of antidepressants may reveal the identity of medication to participants or investigators and thus may bias the results of conventional trials using inert placebos. Using an 'active' placebo which mimics some of the side effects of antidepressants may help to counteract this potential bias. OBJECTIVES: To investigate the efficacy of antidepressants when compared with 'active' placebos. SEARCH STRATEGY: The Cochrane Collaboration Depression, Anxiety and Neurosis review groups's search strategy was used to search MEDLINE (1966-2000), PsychLIT (1980-2000) and EMBASE (1974-2000) and this was last done in July 2000. Reference lists from relevant articles and textbooks were searched and 12 specialist journals were handsearched up to 1996. SELECTION CRITERIA: Randomised and quasi randomised controlled trials comparing antidepressants with active placebos in people with depression. DATA COLLECTION AND ANALYSIS: Since many different outcome measures were used a standard measure of effect was calculated for each trial. A subgroup analysis of inpatient and outpatient trials was conducted. Two reviewers independently assessed whether each trial met inclusion criteria. MAIN RESULTS: Nine studies involving 751 participants were included. Two of them produced effect sizes which showed a consistent and statistically significant difference in favour of the active drug. Combining all studies produced a pooled estimate of effect of 0.39 standard deviations (confidence interval, 0.24 to 0.54) in favour of the antidepressant measured by improvement in mood. There was high heterogeneity due to one strongly positive trial. Sensitivity analysis omitting this trial reduced the pooled effect to 0.17 (0.00 to 0.34). The pooled effect for inpatient and outpatient trials was highly sensitive to decisions about which combination of data was included but inpatient trials produced the lowest effects. REVIEWER'S CONCLUSIONS: The more conservative estimates from the present analysis found that differences between antidepressants and active placebos were small. This suggests that unblinding effects may inflate the efficacy of antidepressants in trials using inert placebos. Further research into unblinding is warranted.

Antidepressive Agents↗
PubMed2001

Is "somatisation" a defense against the acknowledgment of psychiatric disorder?

OBJECTIVE: To determine whether experiencing physical symptoms is associated with a denial of psychological distress in individuals with probable psychiatric disorder. METHODS: A nested case-control study was performed using data from a national birth cohort study. All subjects who scored above threshold on a case-finding questionnaire of psychiatric disorder were identified. Those who in a separate question endorsed the presence of psychiatric disorder ("acknowledgers") were compared with those who did not. RESULTS: Acknowledgers were more likely to be female, better educated and have more severe current and past psychiatric disorder. They were also more likely to report multiple physical symptoms, even when potential confounders and severity of psychiatric disorder were controlled. CONCLUSION: There is no evidence that experiencing multiple physical symptoms helps the individual deny the presence of psychiatric disorder.

Adult↗
PubMed2001

Medically unexplained symptoms: an epidemiological study in seven specialities.

OBJECTIVES: This study aimed to estimate the prevalence and risk factors for medically unexplained symptoms across a variety of specialities. METHODS: A cross-sectional survey was conducted at two general hospitals in southeast London between 1995 and 1997. Eight hundred and ninety consecutive new patients from seven outpatient clinics were included. Demographic and clinical characteristic variables were assessed. RESULTS: Five hundred eighty-two (65%) of the subjects surveyed returned completed questionnaires. A final diagnosis was available in 550 (62%). Two hundred twenty-eight (52%) fulfilled criteria for medically unexplained symptoms. The highest prevalence was in the gynecology clinic (66%). After adjustment for confounders, medically unexplained symptoms were associated with being female, younger, and currently employed. Psychiatric morbidity per se was not associated with the presence of medically unexplained symptoms, but was more likely in those complaining of multiple symptoms. Those with medically unexplained symptoms were less disabled, but more likely to use alternative treatment in comparison with those whose symptoms were medically explained. Patients with medically unexplained symptoms were more likely to attribute their illness to physical causes as opposed to lifestyle factors. CONCLUSIONS: Medically unexplained symptoms are common across general/internal medicine and represent the most common diagnosis in some specialities. Medical behavior, training, and management need to take this into account.

Adolescent↗
PubMed2001

How many functional somatic syndromes?

OBJECTIVE: Patients with medically unexplained symptoms are given diagnoses dependent upon the particular medical specialty consulted--irritable bowel syndrome in gastroenterology, fibromyalgia in rheumatology and others. The purpose of this paper is to establish whether these 13 different syndromes are discrete entities. METHODS: Consecutive new patients in seven outpatient clinics at two general hospitals were recruited. Patients completed questionnaires measuring symptoms and demographic data. Case notes were reviewed to ascertain whether the presenting symptoms were medically explained 3 months after the initial visit. RESULTS: Complete data were available for 550 subjects. With 37 unexplained symptoms included in the model, 30% of the total variance could be explained by one factor using unrotated principal component analysis. When the 13 identified functional syndromes were included, it was evident that functional syndromes could not be assumed to be independent. A two-factor model was the best fit for the present data after rotation. CONCLUSIONS: This study suggests that the existence of distinct functional somatic syndromes (FSSynd) as defined clinically in medicine should be reconsidered.

Cross-Sectional Studies↗
PubMed2001

Patients' perceptions of medical care in chronic fatigue syndrome.

This study investigated perceptions of medical care among patients with chronic fatigue syndrome (CFS) referred to a specialist clinic. Sixty-eight patients completed a questionnaire survey on their overall satisfaction with medical care received since the onset of their illness, and their views on specific aspects of care. Two-thirds of patients were dissatisfied with the quality of medical care received. Dissatisfied patients were significantly more likely to describe delay, dispute or confusion over diagnosis; to have received and rejected a psychiatric diagnosis; to perceive doctors as dismissive, skeptical or not knowledgeable about CFS and to feel that the advice given was inadequate or conflicting. Satisfied patients were significantly more likely to perceive doctors as caring, supportive and interested in their illness; to state that they did not expect their doctors to cure CFS and to perceive their GP or hospital doctor as the source of greatest help during their illness. Many patients were critical of the paucity of treatment, but this was not associated with overall satisfaction. The findings suggest that medical care was evaluated less on the ability of doctors to treat CFS, and more on their interpersonal and informational skills. Dissatisfaction with these factors is likely to impede the development of a therapeutic doctor-patient alliance, which is central to the effective management of CFS. The findings suggest a need for better communication and better education of doctors in the diagnosis and management of CFS.

Adult↗
PubMed2001

The neuroendocrinology of chronic fatigue syndrome and fibromyalgia.

BACKGROUND: Disturbance of the HPA axis may be important in the pathophysiology of chronic fatigue syndrome (CFS) and fibromyalgia. Symptoms may be due to: (1) low circulating cortisol; (2) disturbance of central neurotransmitters; or (3) disturbance of the relationship between cortisol and central neurotransmitter function. Accumulating evidence of the complex relationship between cortisol and 5-HT function, make some form of hypothesis (3) most likely. We review the methodology and results of studies of the HPA and other neuroendocrine axes in CFS. METHOD: Medline, Embase and Psychlit were searched using the Cochrane Collaboration strategy. A search was also performed on the King's College CFS database, which includes over 3000 relevant references, and a citation analysis was run on the key paper (Demitrack et al. 1991). RESULTS: One-third of the studies reporting baseline cortisol found it to be significantly low, usually in one-third of patients. Methodological differences may account for some of the varying results. More consistent is the finding of reduced HPA function, and enhanced 5-HT function on neuroendocrine challenge tests. The opioid system, and arginine vasopressin (AVP) may also be abnormal, though the growth hormone (GH) axis appears to be intact, in CFS. CONCLUSIONS: The significance of these changes, remains unclear. We have little understanding of how neuroendocrine changes relate to the experience of symptoms, and it is unclear whether these changes are primary, or secondary to behavioural changes in sleep or exercise. Longitudinal studies of populations at risk for CFS will help to resolve these issues.

Adrenocorticotropic Hormone↗
PubMed2001

Causal attributions for somatic sensations in patients with chronic fatigue syndrome and their partners.

BACKGROUND: Patients with chronic fatigue syndrome (CFS) often make somatic attributions for their illness which has been associated with poor outcome. A tendency to make somatic attributions in general may be a vulnerability factor for the development of CFS. METHODS: This cross-sectional study based on self-report questionnaire data aimed to investigate the type of attributions for symptoms made by patients with CFS and to compare this to attributions made by their partners. It was hypothesized that patients with CFS would make more somatic attributions for their own symptoms than control subjects and that partners of patients with CFS would make more somatic attributions for their ill relative's symptoms but would be similar to controls regarding their own symptoms. Fifty patients with CFS were compared to 50 controls from a fracture clinic in the same hospital and 46 relatives living with the patients with CFS. A modified Symptom Interpretation Questionnaire was used to assess causal attributions. RESULTS: CFS patients were more likely to make somatic attributions for their symptoms. The relatives of patients with CFS made significantly more somatic attributions for symptoms in their ill relative. However, they were like the fracture clinic controls in terms of making predominantly normalizing attributions for their own symptoms. CONCLUSIONS: The data support modification of existing cognitive behavioural treatments for CFS to investigate whether addressing partners' attributions for patients' symptoms improves recovery in the patient. Furthermore, a tendency to make somatic attributions for symptoms may be a vulnerability factor for the development of CFS.

Adolescent↗
PubMed2001

Lack of association between HLA genotype and chronic fatigue syndrome.

Although the aetiology of chronic fatigue syndrome is controversial, evidence that infective agents including viruses may have a role in the development of the condition has led to studies seeking an association with the immunomodulatory HLA genes. In the present study, we sought to extend previous work using a well-characterized patient group and modern HLA genotyping techniques. Fifty-eight patients were phenotyped for HLA A and B by microcytotoxicity and genotyped for HLA DRB, DQB and DPB by PCR oligoprobing, and the frequencies of antigens so assigned were compared with those from a control group of 134. No significant differences in HLA frequencies were found between patient and control groups. Thus, this study does not confirm previous findings of an HLA association with chronic fatigue syndrome, suggesting that neither presentation of viral antigen by HLA class I nor antigen processing genes in the HLA region is a major contributory factor in the development of the disease.

Alleles↗
PubMed2001

What is chronic fatigue syndrome? Heterogeneity within an international multicentre study.

OBJECTIVE: We sought to compare the characteristics of patients presenting with chronic fatigue (CF) and related syndromes in eight international centres and to subclassify these subjects based on symptom profiles. The validity of the subclasses was then tested against clinical data. METHOD: Subjects with a clinical diagnosis of CF completed a 119-item self-report questionnaire to provide clinical symptom data and other information such as illness course and functional impairment. Subclasses were generated using a principal components-like analysis followed by latent profile analysis (LPA). RESULTS: 744 subjects returned complete data sets (mean age 40.8 years, mean length of illness 7.9 years, female to male ratio 3:1). Overall, the subjects had a high rate of reporting typical CF symptoms (fatigue, neuropsychological dysfunction, sleep disturbance). Using LPA, two subclasses were generated. Class one (68% sample) was characterized by: younger age, lower female to male ratio; shorter episode duration; less premorbid, current and familial psychiatric morbidity; and, less functional disability. Class two subjects (32%) had features more consistent with a somatoform illness. There was substantial variation in subclass prevalences between the study centres (Class two range 6-48%). CONCLUSIONS: Criteria-based approaches to the diagnosis of CF and related syndromes do not select a homogeneous patient group. While substratification of patients is essential for further aetiological and treatment research, the basis for allocating such subcategories remains controversial.

Adult↗
PubMed2001

Ethnic density and deliberate self harm; a small area study in south east London.

STUDY OBJECTIVE: Relative risks are frequently used to convey how strongly outcomes like mental illness and suicidal behaviour are associated with personal characteristics like ethnic background. This study examined whether RRs for deliberate self harm (DSH) in ethnic groups vary between small areas according to their ethnic mix. DESIGN: Small area study of DSH rates in ethnic groups, by local ethnic density, using negative binomial regression. SETTING: 73 south London electoral wards, 1994-1997. SUBJECTS: 1643 people attending casualty after DSH. MAIN RESULTS: African-Caribbean and Asian DSH rates, relative to the white population, varied between wards. A linear model indicated a decline by factors (relative rate ratios) 0.76 (95% confidence intervals (CI) 0.64 to 0.90) and 0.59 (95% CI 0.36 to 0.97) respectively per SD increase in the local size of these minority populations. However, for both groups, an inverted U shaped curve provided a better fit for the link between the relative DSH rate in these groups and their local population density. CONCLUSIONS: The DSH rate of minority groups relative to the white group is low (suggesting protection) in some areas, and high (suggesting risk) elsewhere. This has implications for management of suicidal behaviour in ethnic groups but also for interpretation, and policy implementation, of research on risk for suicidal behaviour, and, probably, many other outcomes. Relative risks or rates are not stable indicators of association in psychiatric epidemiology.

Adult↗