Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where John Evans is active.

Publication


Featured researches published by John Evans.


BMJ | 2012

Effectiveness of multifaceted educational programme to reduce antibiotic dispensing in primary care: Practice based randomised controlled trial

Christopher Collett Butler; Sharon Anne Simpson; Frank David John Dunstan; Stephen Rollnick; David Cohen; David Gillespie; Meirion Rhys Evans; lecturer in epidemiology; M Fasihul Alam; Marie-Jet Bekkers; John Evans; Laurence Moore; Robin Howe; Jamie Hayes; Monika Hare; Kerenza Hood

Objective To evaluate the effectiveness and costs of a multifaceted flexible educational programme aimed at reducing antibiotic dispensing at the practice level in primary care. Design Randomised controlled trial with general practices as the unit of randomisation and analysis. Clinicians and researchers were blinded to group allocation until after randomisation. Setting 68 general practices with about 480u2009000 patients in Wales, United Kingdom. Participants 34 practices were randomised to receive the educational programme and 34 practices to be controls. 139 clinicians from the intervention practices and 124 from control practices had agreed to participate before randomisation. Practice level data covering all the clinicians in the 68 practices were analysed. Interventions Intervention practices followed the Stemming the Tide of Antibiotic Resistance (STAR) educational programme, which included a practice based seminar reflecting on the practices’ own dispensing and resistance data, online educational elements, and practising consulting skills in routine care. Control practices provided usual care. Main outcome measures Total numbers of oral antibiotic items dispensed for all causes per 1000 practice patients in the year after the intervention, adjusted for the previous year’s dispensing. Secondary outcomes included reconsultations, admissions to hospital for selected causes, and costs. Results The rate of oral antibiotic dispensing (items per 1000 registered patients) decreased by 14.1 in the intervention group but increased by 12.1 in the control group, a net difference of 26.1. After adjustment for baseline dispensing rate, this amounted to a 4.2% (95% confidence interval 0.6% to 7.7%) reduction in total oral antibiotic dispensing for the year in the intervention group relative to the control group (P=0.02). Reductions were found for all classes of antibiotics other than penicillinase-resistant penicillins but were largest and significant individually for phenoxymethylpenicillins (penicillin V) (7.3%, 0.4% to 13.7%) and macrolides (7.7%, 1.1% to 13.8%). There were no significant differences between intervention and control practices in the number of admissions to hospital or in reconsultations for a respiratory tract infection within seven days of an index consultation. The mean cost of the programme was £2923 (€3491,


Proceedings of the National Academy of Sciences of the United States of America | 2016

Neural correlates of the LSD experience revealed by multimodal neuroimaging

Robin L. Carhart-Harris; Suresh Daniel Muthukumaraswamy; Leor Roseman; Mendel Kaelen; W. Droog; Kieran C. Murphy; Enzo Tagliazucchi; E.E. Schenberg; T. Nest; Csaba Orban; Robert Leech; L.T. Williams; Tim M. Williams; Mark Bolstridge; B. Sessa; John McGonigle; Martin I. Sereno; David E. Nichols; Peter J. Hellyer; Peter Hobden; John Evans; Krish Devi Singh; Richard Geoffrey Wise; H.V. Curran; Amanda Feilding; David Nutt

4572) per practice (SD £1187). There was a 5.5% reduction in the cost of dispensed antibiotics in the intervention group compared with the control group (−0.4% to 11.4%), equivalent to a reduction of about £830 a year for an average intervention practice. Conclusion The STAR educational programme led to reductions in all cause oral antibiotic dispensing over the subsequent year with no significant change in admissions to hospital, reconsultations, or costs. Trial registration ISRCT No 63355948.


Schizophrenia Bulletin | 2013

Functional Connectivity Measures After Psilocybin Inform a Novel Hypothesis of Early Psychosis

Robin L. Carhart-Harris; Robert Leech; David Erritzoe; Tim M. Williams; James Stone; John Evans; David J. Sharp; Amanda Feilding; Richard Geoffrey Wise; David Nutt

Significance Lysergic acid diethylamide (LSD), the prototypical “psychedelic,” may be unique among psychoactive substances. In the decades that followed its discovery, the magnitude of its effect on science, the arts, and society was unprecedented. LSD produces profound, sometimes life-changing experiences in microgram doses, making it a particularly powerful scientific tool. Here we sought to examine its effects on brain activity, using cutting-edge and complementary neuroimaging techniques in the first modern neuroimaging study of LSD. Results revealed marked changes in brain blood flow, electrical activity, and network communication patterns that correlated strongly with the drug’s hallucinatory and other consciousness-altering properties. These results have implications for the neurobiology of consciousness and for potential applications of LSD in psychological research. Lysergic acid diethylamide (LSD) is the prototypical psychedelic drug, but its effects on the human brain have never been studied before with modern neuroimaging. Here, three complementary neuroimaging techniques: arterial spin labeling (ASL), blood oxygen level-dependent (BOLD) measures, and magnetoencephalography (MEG), implemented during resting state conditions, revealed marked changes in brain activity after LSD that correlated strongly with its characteristic psychological effects. Increased visual cortex cerebral blood flow (CBF), decreased visual cortex alpha power, and a greatly expanded primary visual cortex (V1) functional connectivity profile correlated strongly with ratings of visual hallucinations, implying that intrinsic brain activity exerts greater influence on visual processing in the psychedelic state, thereby defining its hallucinatory quality. LSD’s marked effects on the visual cortex did not significantly correlate with the drug’s other characteristic effects on consciousness, however. Rather, decreased connectivity between the parahippocampus and retrosplenial cortex (RSC) correlated strongly with ratings of “ego-dissolution” and “altered meaning,” implying the importance of this particular circuit for the maintenance of “self” or “ego” and its processing of “meaning.” Strong relationships were also found between the different imaging metrics, enabling firmer inferences to be made about their functional significance. This uniquely comprehensive examination of the LSD state represents an important advance in scientific research with psychedelic drugs at a time of growing interest in their scientific and therapeutic value. The present results contribute important new insights into the characteristic hallucinatory and consciousness-altering properties of psychedelics that inform on how they can model certain pathological states and potentially treat others.


British Journal of Psychiatry | 2012

Implications for psychedelic-assisted psychotherapy: functional magnetic resonance imaging study with psilocybin.

Robin L. Carhart-Harris; Robert Leech; Tim M. Williams; David Erritzoe; N. Abbasi; T. Bargiotas; Peter Hobden; David J. Sharp; John Evans; Amanda Feilding; Richard Geoffrey Wise; David Nutt

Psilocybin is a classic psychedelic and a candidate drug model of psychosis. This study measured the effects of psilocybin on resting-state network and thalamocortical functional connectivity (FC) using functional magnetic resonance imaging (fMRI). Fifteen healthy volunteers received intravenous infusions of psilocybin and placebo in 2 task-free resting-state scans. Primary analyses focused on changes in FC between the default-mode- (DMN) and task-positive network (TPN). Spontaneous activity in the DMN is orthogonal to spontaneous activity in the TPN, and it is well known that these networks support very different functions (ie, the DMN supports introspection, whereas the TPN supports externally focused attention). Here, independent components and seed-based FC analyses revealed increased DMN-TPN FC and so decreased DMN-TPN orthogonality after psilocybin. Increased DMN-TPN FC has been found in psychosis and meditatory states, which share some phenomenological similarities with the psychedelic state. Increased DMN-TPN FC has also been observed in sedation, as has decreased thalamocortical FC, but here we found preserved thalamocortical FC after psilocybin. Thus, we propose that thalamocortical FC may be related to arousal, whereas DMN-TPN FC is related to the separateness of internally and externally focused states. We suggest that this orthogonality is compromised in early psychosis, explaining similarities between its phenomenology and that of the psychedelic state and supporting the utility of psilocybin as a model of early psychosis.


Biological Psychiatry | 2012

Cingulum White Matter in Young Women at Risk of Depression: The Effect of Family History and Anhedonia

Paul Anthony Keedwell; Rosanna Chapman; Kat Christiansen; Heather N. Richardson; John Evans; Derek K. Jones

BACKGROUNDnPsilocybin is a classic psychedelic drug that has a history of use in psychotherapy. One of the rationales for its use was that it aids emotional insight by lowering psychological defences.nnnAIMSnTo test the hypothesis that psilocybin facilitates access to personal memories and emotions by comparing subjective and neural responses to positive autobiographical memories under psilocybin and placebo.nnnMETHODnTen healthy participants received two functional magnetic resonance imaging scans (2 mg intravenous psilocybin v. intravenous saline), separated by approximately 7 days, during which they viewed two different sets of 15 positive autobiographical memory cues. Participants viewed each cue for 6 s and then closed their eyes for 16 s and imagined re-experiencing the event. Activations during this recollection period were compared with an equivalent period of eyes-closed rest. We split the recollection period into an early phase (first 8 s) and a late phase (last 8 s) for analysis.nnnRESULTSnRobust activations to the memories were seen in limbic and striatal regions in the early phase and the medial prefrontal cortex in the late phase in both conditions (P<0.001, whole brain cluster correction), but there were additional visual and other sensory cortical activations in the late phase under psilocybin that were absent under placebo. Ratings of memory vividness and visual imagery were significantly higher after psilocybin (P<0.05) and there was a significant positive correlation between vividness and subjective well-being at follow-up (P<0.01).nnnCONCLUSIONSnEvidence that psilocybin enhances autobiographical recollection implies that it may be useful in psychotherapy either as a tool to facilitate the recall of salient memories or to reverse negative cognitive biases.


BMC Family Practice | 2010

Enhancing the quality of antibiotic prescribing in Primary Care: Qualitative evaluation of a blended learning intervention

Marie-Jet Bekkers; Sharon Anne Simpson; Frank David John Dunstan; Kerry Hood; Monika Hare; John Evans; Christopher Collett Butler

BACKGROUNDnAltered white matter microstructure in tracts integral to mood regulation networks could underlie vulnerability to major depressive disorder (MDD). Guided by functional magnetic resonance studies, we explored whether a positive family history of MDD (FH+) and anhedonia (reduced capacity for pleasure) were associated with altered white matter microstructure in the cingulum bundles and uncinate fasciculi.nnnMETHODSnDiffusion tensor magnetic resonance imaging data were acquired on 34 healthy female student volunteers (mean age 22 years). Exclusion criteria included other current or previous psychiatric disorder, current depression, and current psychotropic medication. Family history was determined using established criteria. Fiber tractography was performed for each individual for a priori tracts of interest and a comparison tract. Mean fractional anisotropy (FA), an index of microstructure, was calculated for each tract.nnnRESULTSnTracts were reconstructed in 18 FH+ individuals and 15 FH- individuals, who did not differ by age or subclinical depressive symptoms. FH+ subjects had 3% to 5% lower FA in the right and left cingulum bundles than FH- individuals (p = .012, p = .059, respectively). Post hoc analysis demonstrated 8% lower FA in the left subgenual cingulate (p = .007). Hedonic tone correlated positively with FA in the right and left cingulum bundles (r = .342, p = .052; r = .477, p = .005, respectively), and the left subgenual cingulum (r = .500, p = .003).nnnCONCLUSIONSnBoth family history of MDD and subclinical anhedonia are associated with reduced FA in the bilateral cingulum bundles, particularly in the left subgenual cingulum. Altered cingulum white matter architecture is implicated in the etiology of MDD.


Tourism Management | 1993

Tourism graduates: a case of over-production

John Evans

BackgroundThe Stemming the Tide of Antibiotic Resistance (STAR) Educational Program aims to enhance the quality of antibiotic prescribing and raise awareness about antibiotic resistance among general medical practitioners. It consists of a seven part, theory-based blended learning program that includes online reflection on clinicians own practice, presentation of research evidence and guidelines, a practice-based seminar focusing on participants own antibiotic prescribing and resistance rates in urine samples sent from their practice, communication skills training using videos of simulated patients in routine surgeries, and participation in a web forum. Effectiveness was evaluated in a randomised controlled trial in which 244 GPs and Nurse Practitioners and 68 general practices participated. This paper reports part of the process evaluation of that trial.MethodsSemi-structured, digitally recorded, and transcribed telephone interviews with 31 purposively sampled trial participants analysed using thematic content analysis.ResultsThe majority of participants reported increased awareness of antibiotic resistance, greater self-confidence in reducing antibiotic prescribing and at least some change in consultation style and antibiotic prescribing behaviour. Reported practical changes included adopting a practice-wide policy of antibiotic prescription reduction. Many GPs also reported increased insight into patients expectations, ultimately contributing to improved doctor-patient rapport. The components of the intervention put forward as having the greatest influence on changing clinician behaviour were the up-to-date research evidence resources, simple and effective communication skills presented in on-line videos, and presentation of the practices own antibiotic prescribing levels combined with an overview of local resistance data.ConclusionParticipants regarded this complex blended learning intervention acceptable and feasible, and reported wide-ranging, positive changes in attitudes and clinical practice as a result of participating in the STAR Educational Program.Trial registrationCurrent Controlled Trials ISRCTN63355948


Journal of Psychiatric Research | 2015

Exploring neural dysfunction in 'clinical high risk' for psychosis: a quantitative review of fMRI studies.

Anirban Dutt; Huai-Hsuan Tseng; Leon Fonville; Mark Drakesmith; Liang Su; John Evans; Stanley Zammit; Derek K. Jones; Glyn Lewis; Anthony S. David

Abstract There are already too many tourism graduates in the UK for the jobs available in the industry and with economic recovery uncertain-prospects for the future do not look good. Moreover, many employers do not consider a degree in tourism to be a prerequisite for employment, the result, perhaps, of ignorance and confusion about what is on offer. These are the findings of the recent CNAA report on tourism courses. The author argues that they must be heeded and action taken to improve the situation.


Archive | 2011

Children’s Bodies, Surveillance and the Obesity Crisis

Emma Rich; John Evans; Laura De Pian

Individuals at clinical high risk (CHR) of developing psychosis present with widespread functional abnormalities in the brain. Cognitive deficits, including working memory (WM) problems, as commonly elicited by n-back tasks, are observed in CHR individuals. However, functional MRI (fMRI) studies, comprising a heterogeneous cluster of general and social cognition paradigms, have not necessarily demonstrated consistent and conclusive results in this population. Hence, a comprehensive review of fMRI studies, spanning almost one decade, was carried out to observe for general trends with respect to brain regions and cognitive systems most likely to be dysfunctional in CHR individuals. 32 studies were included for this review, out of which 22 met the criteria for quantitative analysis using activation likelihood estimation (ALE). Task related contrast activations were firstly analysed by comparing CHR and healthy control participants in the total pooled sample, followed by a comparison of general cognitive function studies (excluding social cognition paradigms), and finally by only looking at n-back working memory task based studies. Findings from the ALE implicated four key dysfunctional and distinct neural regions in the CHR group, namely the right inferior parietal lobule (rIPL), the left medial frontal gyrus (lmFG), the left superior temporal gyrus (lSTG) and the right fronto-polar cortex (rFPC) of the superior frontal gyrus (SFG). Narrowing down to relatively few significant dysfunctional neural regions is a step forward in reducing the apparent ambiguity of overall findings, which would help to target specific neural regions and pathways of interest for future research in CHR populations.


NeuroImage: Clinical | 2015

Hyperconnectivity in juvenile myoclonic epilepsy: a network analysis.

Karen Caeyenberghs; Hugh Powell; Rhys Huw Thomas; Lisa Brindley; Carla Church; John Evans; Suresh Daniel Muthukumaraswamy; Derek K. Jones; Khalid Hamandi

Lyon (2002: 1) suggests that whilst work in the field of surveillance studies is broad and diverse, ‘what they have in common is that, for whatever reason, people and populations are under scrutiny’. Increasing amounts of intervention into people’s lives in a quest to monitor and regulate their diets, health, body size and shape is one way in which people have fallen prey to increasing levels of surveillance in society. As evidenced in previous chapters, the construction of obesity as a ‘health crisis’ has further propagated what Armstrong (1995) refers to as ‘Surveillance Medicine’: nSurveillance Medicine requires the dissolution of the distinct clinical categories of healthy and ill as it attempts to bring everyone within its network of visibility. Therefore one of the earliest expressions of Surveillance Medicine — and a vital precondition for its continuing proliferation — was the problematisation of the normal. n n(Armstrong, 1995: 395)

Collaboration


Dive into the John Evans's collaboration.

Top Co-Authors

Avatar

Emma Rich

Loughborough University

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

David Nutt

Imperial College London

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Robert Leech

Imperial College London

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge