7 results
A systematic review of the cognitive effects of the COMT inhibitor, tolcapone, in adult humans
- Emilia Kings, Konstantinos Ioannidis, Jon E. Grant, Samuel R. Chamberlain
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- Journal:
- CNS Spectrums , First View
- Published online by Cambridge University Press:
- 15 March 2024, pp. 1-10
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Objective
The catechol-o-methyltransferase (COMT) inhibitor tolcapone constitutes a potentially useful probe of frontal cortical dopaminergic function. The aim of this systematic review was to examine what is known of effects of tolcapone on human cognition in randomized controlled studies.
MethodsThe study protocol was preregistered on the Open Science Framework. A systematic review was conducted using PubMed to identify relevant randomized controlled trials examining the effects of tolcapone on human cognition. Identified articles were then screened against inclusion and exclusion criteria.
ResultsOf the 22 full-text papers identified, 13 randomized control trials were found to fit the pre-specified criteria. The most consistent finding was that tolcapone modulated working memory; however, the direction of effect appeared to be contingent on the COMT polymorphism (more consistent evidence of improvement in Val–Val participants). There were insufficient nature and number of studies for meta-analysis.
ConclusionThe cognitive improvements identified upon tolcapone administration, in some studies, are likely to be due to the level of dopamine in the prefrontal cortex being shifted closer to its optimum, per an inverted U model of prefrontal function. However, the results should be interpreted cautiously due to the small numbers of studies. Given the centrality of cortical dopamine to understanding human cognition, studies using tolcapone in larger samples and across a broader set of cognitive domains would be valuable. It would also be useful to explore the effects of different dosing regimens (different doses; and single versus repeated administration).
Cognition in trichotillomania: a meta-analysis
- Aliza Ali, Konstantinos Ioannidis, Jon E. Grant, Samuel R. Chamberlain
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- CNS Spectrums , First View
- Published online by Cambridge University Press:
- 13 March 2024, pp. 1-8
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Objective
Trichotillomania (TTM) is a mental health disorder characterized by repetitive urges to pull out one’s hair. Cognitive deficits have been reported in people with TTM compared to controls; however, the current literature is sparse and inconclusive about affected domains. We aimed to synthesize research on cognitive functioning in TTM and investigate which cognitive domains are impaired.
MethodsAfter preregistration on the International Prospective Register of Systematic Reviews (PROSPERO), we conducted a comprehensive literature search for papers examining cognition in people with TTM versus controls using validated tests. A total of 793 papers were screened using preestablished inclusion/exclusion criteria, yielding 15 eligible studies. Random-effects meta-analysis was conducted for 12 cognitive domains.
ResultsMeta-analysis demonstrated significant deficits in motor inhibition and extradimensional (ED) shifting in people with TTM versus controls as measured by the stop-signal task (SST) (Hedge’s g = 0.45, [CI: 0.14, 0.75], p = .004) and ED set-shift task (g = 0.38, [CI: 0.13, 0.62], p = .003), respectively. There were no significant between-group differences in the other cognitive domains tested: verbal learning, intradimensional (ID) shifting, road map spatial ability, pattern recognition, nonverbal memory, executive planning, spatial span length, Stroop inhibition, Wisconsin card sorting, and visuospatial functioning. Findings were not significantly moderated by study quality scores.
ConclusionsMotor inhibition and ED set-shifting appear impaired in TTM. However, a cautious interpretation of results is necessary as samples were relatively small and frequently included comorbidities. Treatment interventions seeking to improve inhibitory control and cognitive flexibility merit exploration for TTM.
Chapter 7 - Eating Disorders and Over-Exercise
- from Section 1 - From Exercise to Addiction: An Introduction to the Phenomenon
- Edited by Ornella Corazza, University of Hertfordshire and University of Trento, Italy, Artemisa Rocha Dores, Polytechnic Institute of Porto and University of Porto, Portugal
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- The Body in the Mind
- Published online:
- 30 March 2023
- Print publication:
- 06 April 2023, pp 103-120
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Summary
Dysfunctional exercise is one of the most challenging behaviours in individuals with eating disorders, among whom it makes a significant contribution to morbidity and impaired quality of life. This chapter examines the prevalence of dysfunctional exercise symptoms in the context of an eating disorder, the neurobiological basis of dysfunctional exercise symptoms, and the various predisposing and maintaining factors that are involved. It then highlights the need for management and treatment of excessive exercise to address the neurobiological and psychological factors involved, and describes the evidence base for such treatments, especially physiotherapy-based psychological interventions. A multidisciplinary approach to management is recommended, so that treatment can be formulated within the wider context of the individual’s psychosocial difficulties, enabling them to challenge their exercise-related beliefs and behaviour. Finally, two semi-fictional case studies are presented that illustrate common presentations of dysfunctional exercise in eating disorder clinics.
Fruit and vegetable intake among psychiatric inpatients: an electronic health record-based study
- Adelaide Yue, Aida Seyedsalehi, Jonathan Lewis, Konstantinos Ioannidis, Julia Deakin
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- Journal:
- BJPsych Open / Volume 7 / Issue S1 / June 2021
- Published online by Cambridge University Press:
- 18 June 2021, p. S356
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Aims
Psychiatric illness is associated with premature mortality, which is largely attributable to physical health conditions. Low fruit and vegetable intake is a risk factor for cardiovascular disease, which contributes significantly to this disparity in physical health. This study used routinely collected data from electronic health records to assess fruit and vegetable intake among psychiatric inpatients across a UK mental health trust.
MethodWe conducted an anonymised search of de-identified electronic patient records from the Cambridgeshire and Peterborough NHS Foundation Trust (CPFT) research database. We collected data on ICD-10 diagnosis and fruit and vegetable intake for patients aged 18 years or over, with a recorded ICD-10 psychiatric diagnosis, admitted to CPFT inpatient facilities between March 2013 and January 2019 inclusive (n = 1031). Information on fruit and vegetable intake is recorded as part of a General Health and Lifestyle questionnaire, routinely performed within a week of admission. Fruit and vegetable intake in different ICD-10 diagnostic categories was compared using a one-way ANOVA.
ResultAmong patients for whom data on fruit and vegetable intake was recorded (n = 768), the prevalence of low fruit and vegetable intake (defined as <5 portions/day) was 75.9%, and mean fruit and vegetable intake was 2.85 portions/day (95% CI 2.72-2.98). Fruit and vegetable intake was lowest among patients with schizophrenia (mean = 2.3 portions/day), significantly worse than other diagnostic groups. In patients with schizophrenia, prevalence of low fruit and vegetable intake was 86.5%.
ConclusionLow fruit and vegetable intake is common among CPFT psychiatric inpatients, particularly those with schizophrenia. Interventions to improve dietary habits, such as increasing tailored for individuals with psychiatric illness may help to reduce the risk of physical illness.
Problematic internet use: an exploration of associations between cognition and COMT rs4818, rs4680 haplotypes
- Konstantinos Ioannidis, Sarah A. Redden, Stephanie Valle, Samuel R. Chamberlain, Jon E. Grant
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- Journal:
- CNS Spectrums / Volume 25 / Issue 3 / June 2020
- Published online by Cambridge University Press:
- 04 June 2019, pp. 409-418
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Objective
Problematic internet users suffer from impairment in a variety of cognitive domains. Research suggests that COMT haplotypes exert differential effects on cognition. We sought to investigate differences in the genetic profiles of problematic internet users and whether those could shed light on potential cognitive differences.
MethodsWe recruited 206 non-treatment seeking participants with heightened impulsive traits and obtained cross-sectional demographic, clinical, and cognitive data as well as the genetic haplotypes of COMT rs4680 and rs4818. We identified 24 participants who presented with problematic internet use (PIU) and compared PIU and non-PIU participants using one-way analysis of variance (ANOVA) and chi square as appropriate.
ResultsPIU was associated with worse performance on decision making, rapid visual processing, and spatial working memory tasks. Genetic variants were associated with altered cognitive performance, but rates of PIU did not statistically differ for particular haplotypes of COMT.
ConclusionThis study indicates that PIU is characterized by deficits in decision making and working memory domains; it also provides evidence for elevated impulsive responses and impaired target detection on a sustained attention task, which is a novel area worth exploring further in future work. The effects observed in the genetic influences on cognition of PIU subjects imply that the genetic heritable components of PIU may not lie within the genetic loci influencing COMT function and cognitive performance; or that the genetic component in PIU involves many genetic polymorphisms each conferring only a small effect.
Cognitive deficits in problematic internet use: meta-analysis of 40 studies
- Konstantinos Ioannidis, Roxanne Hook, Anna E. Goudriaan, Simon Vlies, Naomi A. Fineberg, Jon E. Grant, Samuel R. Chamberlain
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- Journal:
- The British Journal of Psychiatry / Volume 215 / Issue 5 / November 2019
- Published online by Cambridge University Press:
- 20 February 2019, pp. 639-646
- Print publication:
- November 2019
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Background
Excessive use of the internet is increasingly recognised as a global public health concern. Individual studies have reported cognitive impairment in problematic internet use (PIU), but have suffered from various methodological limitations. Confirmation of cognitive deficits in PIU would support the neurobiological plausibility of this disorder.
AimsTo conduct a rigorous meta-analysis of cognitive performance in PIU from case–control studies; and to assess the impact of study quality, the main type of online behaviour (for example gaming) and other parameters on the findings.
MethodA systematic literature review was conducted of peer-reviewed case–controlled studies comparing cognition in people with PIU (broadly defined) with that of healthy controls. Findings were extracted and subjected to a meta-analysis where at least four publications existed for a given cognitive domain of interest.
ResultsThe meta-analysis comprised 2922 participants across 40 studies. Compared with controls, PIU was associated with significant impairment in inhibitory control (Stroop task Hedge's g = 0.53 (s.e. = 0.19–0.87), stop-signal task g = 0.42 (s.e. = 0.17–0.66), go/no-go task g = 0.51 (s.e. = 0.26–0.75)), decision-making (g = 0.49 (s.e. = 0.28–0.70)) and working memory (g = 0.40 (s.e. = 0.20–0.82)). Whether or not gaming was the predominant type of online behaviour did not significantly moderate the observed cognitive effects; nor did age, gender, geographical area of reporting or the presence of comorbidities.
ConclusionsPIU is associated with decrements across a range of neuropsychological domains, irrespective of geographical location, supporting its cross-cultural and biological validity. These findings also suggest a common neurobiological vulnerability across PIU behaviours, including gaming, rather than a dissimilar neurocognitive profile for internet gaming disorder.
Declaration of interestS.R.C. consults for Cambridge Cognition and Shire. K.I.’s research activities were supported by Health Education East of England Higher Training Special interest sessions. A.E.G.'s research has been funded by Innovational grant (VIDI-scheme) from ZonMW: (91713354). N.A.F. has received research support from Lundbeck, Glaxo-SmithKline, European College of Neuropsychopharmacology (ECNP), Servier, Cephalon, Astra Zeneca, Medical Research Council (UK), National Institute for Health Research, Wellcome Foundation, University of Hertfordshire, EU (FP7) and Shire. N.A.F. has received honoraria for lectures at scientific meetings from Abbott, Otsuka, Lundbeck, Servier, Astra Zeneca, Jazz pharmaceuticals, Bristol Myers Squibb, UK College of Mental Health Pharmacists and British Association for Psychopharmacology (BAP). N.A.F. has received financial support to attend scientific meetings from RANZCP, Shire, Janssen, Lundbeck, Servier, Novartis, Bristol Myers Squibb, Cephalon, International College of Obsessive-Compulsive Spectrum Disorders, International Society for Behavioral Addiction, CINP, IFMAD, ECNP, BAP, the World Health Organization and the Royal College of Psychiatrists. N.A.F. has received financial royalties for publications from Oxford University Press and payment for editorial duties from Taylor and Francis. J.E.G. reports grants from the National Center for Responsible Gaming, Forest Pharmaceuticals, Takeda, Brainsway, and Roche and others from Oxford Press, Norton, McGraw-Hill and American Psychiatric Publishing outside of the submitted work.
ADHD symptoms in non-treatment seeking young adults: relationship with other forms of impulsivity
- Samuel R. Chamberlain, Konstantinos Ioannidis, Eric W. Leppink, Faiza Niaz, Sarah A. Redden, Jon E. Grant
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- Journal:
- CNS Spectrums / Volume 22 / Issue 1 / February 2017
- Published online by Cambridge University Press:
- 29 September 2016, pp. 22-30
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Objective
Attention-deficit hyperactivity disorder (ADHD) has been associated with various manifestations of impulsivity in adults, including elevated rates of other impulsive disorders, substance use, questionnaire-based impulsivity scores, and inhibitory dysregulation on neurocognitive tests. The relationship between ADHD and all these other forms of impulsivity has yet to be explored within the context of a single comprehensive study.
MethodsA total of 423 young adults, who gambled ≥5 times in the preceding year, were recruited using media advertisements and undertook detailed assessment including structured psychiatric interview, questionnaires, and neurocognitive tests. Participants with ADHD symptoms were identified using the Adult ADHD Self-Report Scale Screener (ASRS-V1.1) and were compared to controls using multivariate analysis of variance (MANOVA).
ResultsADHD symptoms were found in 20.3% of the sample, but only 7.3% of these subjects had ever received a formal diagnosis. ADHD symptoms were associated with significantly lower quality of life, lower self-esteem, higher emotional dysregulation, higher impulsivity questionnaire scores, more problematic Internet use, greater occurrence of psychiatric disorders, and impaired stop-signal reaction times. Of these variables, stop-signal reaction times and Barratt attentional impulsiveness were the strongest predictors of group classification.
ConclusionsADHD symptoms are common and under-diagnosed in young adults who gamble, and are most strongly linked with certain other types of impulsivity (questionnaire- and cognitive-based measures) and with emotional dysregulation, suggesting that these are each important considerations in understanding the pathophysiology of the disorder, but also potential treatment targets. It is necessary to question whether treatment for adult ADHD could be enhanced by considering self-esteem, emotional reactivity, and impaired inhibitory control as specific treatment targets, in addition to the core diagnostic symptoms of the disorder.