Marcus R Munafò

University of Bristol, Bristol, England, United Kingdom

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Publications (290)1634.66 Total impact

  • Marcus R Munafò, Jonathan Flint
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    ABSTRACT: It is now clear that almost all complex traits have a highly polygenic component; that is, their genetic basis consists of relatively frequent risk alleles at a very large number of loci, each making a small contribution to variation, or disease susceptibility. This general conclusion appears to hold for intermediate phenotypes. Therefore, we should not expect these phenotypes to be associated with substantially larger effect sizes than conventional phenotypes. Instead, their usefulness is likely to lie in understanding the mechanism underpinning associations identified via genome-wide association studies of conventional phenotypes.
    Psychophysiology 12/2014; 51(12):1331-2. · 3.29 Impact Factor
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    ABSTRACT: Many studies have explored associations between depression and facial emotion recognition (ER). However, these studies have used various paradigms and multiple stimulus sets, rendering comparisons difficult. Few studies have attempted to determine the magnitude of any effect and whether studies are properly powered to detect it. We conducted a meta-analysis to synthesize the findings across studies on ER in depressed individuals compared to controls.
    Psychological medicine. 11/2014;
  • Sally Adams, Angela S Attwood, Marcus R Munafo
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    ABSTRACT: Nicotine's effects on mood are thought to enhance its addictive potential. However, the mechanisms underlying the effects of nicotine on affect regulation have not been reliably demonstrated in human laboratory studies. We investigated the effects of abstinence (experiment one), and nicotine challenge and expectancy (experiment two) on attentional bias towards facial emotional stimuli differing in emotional valence.
    Nicotine & tobacco research : official journal of the Society for Research on Nicotine and Tobacco. 10/2014;
  • Amy E Taylor, George Davey Smith, Marcus R Munafò
    American journal of epidemiology. 10/2014;
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    ABSTRACT: Smoking-related cues can trigger drug-seeking behaviors, and computer-based interventions that reduce cognitive biases towards such cues may be efficacious and cost-effective cessation aids. In order to optimize such interventions, there needs to be better understanding of the mechanisms underlying the effects of cognitive bias modification (CBM). Here we present a protocol for an investigation of the neural effects of CBM and varenicline in non-quitting daily smokers.
    Trials. 10/2014; 15(1):391.
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    ABSTRACT: Background This study tests whether the genetic predictor (CHRNA5 nicotine receptor gene variants) and an environmental risk factor (partner smoking) interact in the prediction of smoking reduction. Methods Subjects were from a community-based, longitudinal study of women (N = 1,856) who smoked before pregnancy, and a randomized comparative effectiveness smoking cessation trial (N = 1,065). Smoking reduction was defined as the trajectory of self-reported smoking quantities over time in the observational study, and as the trajectory of alveolar CO levels in the cessation trial. Results In the pregnancy study, rs16969968 genotype and partner smoking status interacted such that the smoking reduction was lowest for expectant mothers with high genetic risk and partner smoking, and highest for those with high genetic risk but not partner smoking (interaction of genotype*partner smoking on smoking quantity trajectory slope β=0.071, 95%CI = 0.013, 0.13, p = 0.017). In the clinical trial, a similar interaction was found (interaction β=0.20, 95%CI = 0.049, 0.36, p = 0.010). Furthermore, these associations were moderated by pharmacotherapy such that the interactive relation of genetic and environmental factors occurred in the placebo group, but not in the active pharmacotherapy group (interaction of genotype*partner smoking*pharmacotherapy on CO trajectory slope β=-0.25, 95%CI = -0.42, -.091, p = 0.0023). Conclusions The CHRNA5 genetic risk synergized the effect of partner smoking, producing an especially low likelihood of successful smoking reduction in two complementary studies. This suggests that the genetic vulnerability may be mitigated by altering environmental factors. In addition, cessation pharmacotherapy neutralizes the increase in cessation failure associated with combined genetic and environmental risks, which has possible relevance to treatment algorithms.
    Drug and Alcohol Dependence 10/2014; · 3.14 Impact Factor
  • Jennifer J Ware, Marcus R Munafò
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    ABSTRACT: Tobacco use remains the leading cause of preventable death worldwide. Establishing the genetic aetiology of tobacco use and dependence is an important first step in understanding the neurobiological mechanisms of tobacco use, and in turn the development of effective treatments. In addition, whilst the effects of tobacco use on a broad range of physical illnesses (e.g. lung cancer, respiratory disease, cardiovascular disease) are now well-established, the causal effects of tobacco use on a number of other outcomes remains to be established. Determining the causes and consequences of tobacco use therefore continues to be both a scientific and a public health priority. Here we review emerging methods in genetic research that allow stronger causal inferences to be drawn from observational data.
    Current Psychiatry Reports 10/2014; 16(10):477. · 3.23 Impact Factor
  • Lee Hogarth, Olivia M. Maynard, Marcus R. Munafò
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    ABSTRACT: AimsTo gain insight into the potential impact of plain tobacco packaging policy, two experiments were undertaken to test whether ‘prototype’ plain compared with branded UK cigarette pack stimuli would differentially elicit instrumental tobacco-seeking in a nominal Pavlovian to instrumental transfer (PIT) procedure.Design, Setting, ParticipantsTwo experiments were undertaken at the University of Bristol UK, with a convenience sample of adult smokers (Experiment 1, n = 23, Experiment 2, n = 121).MeasurementIn both experiments, smokers were trained on a concurrent choice procedure in which two responses earned points for cigarettes and chocolate, respectively, before images of branded and plain packs were tested for capacity to elicit the tobacco-seeking response in extinction. The primary outcome was percentage choice of the tobacco- over the chocolate-seeking response in plain pack, branded pack and no-stimulus condition.FindingsBoth experiments found that branded packs primed a greater percentage of tobacco-seeking (overall mean = 62%) than plain packs (overall mean = 53%) and the no-stimulus condition (overall mean = 52%; ps.≤01, ŋp2s ≥.16), and that there was no difference in percentage tobacco-seeking between plain packs and the no-stimulus condition (ps.≥17, ŋp2s ≤.04). Plain tobacco packs showed an overall 9% reduction in the priming of a tobacco choice response compared to branded tobacco packs.Conclusions Plain packaging may reduce smoking in current smokers by degrading cue-elicited tobacco-seeking.
    Addiction 10/2014; · 4.58 Impact Factor
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    ABSTRACT: Objectives To investigate whether associations of smoking with depression and anxiety are likely to be causal, using a Mendelian randomisation approach.Design Mendelian randomisation meta-analyses using a genetic variant (rs16969968/rs1051730) as a proxy for smoking heaviness, and observational meta-analyses of the associations of smoking status and smoking heaviness with depression, anxiety and psychological distress.Participants Current, former and never smokers of European ancestry aged ≥16 years from 25 studies in the Consortium for Causal Analysis Research in Tobacco and Alcohol (CARTA).Primary outcome measures Binary definitions of depression, anxiety and psychological distress assessed by clinical interview, symptom scales or self-reported recall of clinician diagnosis.Results The analytic sample included up to 58 176 never smokers, 37 428 former smokers and 32 028 current smokers (total N=127 632). In observational analyses, current smokers had 1.85 times greater odds of depression
    BMJ Open 10/2014; 4. · 2.06 Impact Factor
  • Nature Biotechnology 09/2014; 32(9):871-873. · 32.44 Impact Factor
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    ABSTRACT: There is a large body of pre-clinical and some clinical data to link the neuropeptide galanin to a range of physiological and pathological functions that include metabolism, depression, and addiction. An enhancer region upstream of the human GAL transcriptional start site has previously been characterised. In-vitro transfection studies in rat hypothalamic neurons demonstrated that the CA allele was 40% less active than the GG allele in driving galanin expression. Our hypothesis was to investigate the effect of this galanin enhancer genotype on a range of variables that relate to the known functions of the galaninergic system in the Avon Longitudinal Study of Parents and Children (ALSPAC) cohort of young adults (N = 169–6,078). Initial findings showed a positive relationship of cannabis usage (OR = 2.070, P = 0.007, N = 406 (individuals who had used cannabis at least once within the last 12 months, total sample size 2731) with the GG haplotype, consistent with the previous published data linking galanin with an increased release of dopamine. As our sample size was relatively small we replicated the analysis in a larger cohort of 2,224 African Americans and 1,840 European Americans, but no discernible trend across genotypes was observed for the relationship with cannabis usage. Further, we found no association of the galanin enhancer genotype with any of the other pathophysiological parameters measured. These findings emphasise that preclinical data does not always predict clinical outcomes in cohort studies, noting that association studies are subject to multiple confounders. © 2014 The Authors. American Journal of Medical Genetics Part B: Neuropsychiatric Genetics published by Wiley Periodicals, Inc.
    American Journal of Medical Genetics Part B Neuropsychiatric Genetics 09/2014; · 3.23 Impact Factor
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    Lee Harrison, Sue Wilson, Marcus R Munafò
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    ABSTRACT: The prevalence of musculoskeletal chronic pain in adolescents is estimated to be approximately 4% to 40%. The development of musculoskeletal pain during teenage years could have a marked impact on physical, psychological and social well-being.
    09/2014; 19(5):e139-e145.
  • Jonathan Flint, Nicholas Timpson, Marcus Munafò
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    ABSTRACT: Intermediate phenotypes are traits positioned somewhere between genetic variation and disease. They represent a target for attempts to find disease-associated genetic variants and elucidation of mechanisms. Psychiatry has been particularly enamoured with intermediate phenotypes, due to uncertainty about disease aetiology, inconclusive results in early psychiatric genetic studies, and their appeal relative to traditional diagnostic categories. In this review, we argue that new genetic findings are relevant to the question of the utility of these constructs. In particular, results from genome-wide association studies of psychiatric disorders now allow an assessment of the potential role of particular intermediate phenotypes. Based on such an analysis, as well as other recent results, we conclude that intermediate phenotypes are likely to be most valuable in understanding mechanism.
    Trends in Neurosciences 09/2014; · 13.58 Impact Factor
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    ABSTRACT: Depressive symptoms and alcohol misuse contribute substantially to the global health burden. These phenotypes often manifest, and frequently co-occur, during adolescence. However, few studies have examined whether both baseline levels of depressive symptoms and change in symptoms are associated with alcohol outcomes. In addition, inconsistent findings could be due to sex differences or the use of different alcohol outcomes. Using data from a prospective population-based cohort in the UK, we estimated trajectories of depressive symptoms from 12 years 10 months to 17 years 10 months, separately for male and female participants. We assessed whether baseline and change in depressive symptoms were associated with use and harmful use of alcohol at 18 years 8 months. Among females, increasing depressive symptoms were associated with increased alcohol use; whilst for males, there was little evidence of this. When examining harmful levels of alcohol use, baseline levels of depressive symptoms in males were weakly related to later harmful alcohol use but this association was attenuated substantially through adjustment for confounders. In contrast, both baseline symptoms and increase in symptoms were associated with later harmful alcohol use in females and these associations were not diminished by confounder adjustment. Elevated depressive symptoms during adolescence are positively associated with increases in both use and harmful use of alcohol at 18 years 8 months. These findings differ between the sexes. Further research is needed to examine the mechanisms underlying the link between depressive symptoms and harmful alcohol use to identify potentially modifiable factors for intervention.
    European Child & Adolescent Psychiatry 08/2014; · 3.70 Impact Factor
  • Jonathan Flint, Marcus R Munafò
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    ABSTRACT: New studies have substantially advanced our understanding of the genetic architecture of schizophrenia, but we are far from identifying the underlying mutations. We may require new approaches to understand the biological implications of insights into the genetics of psychiatric disease.
    Current biology : CB. 08/2014; 24(16):R755-R757.
  • Amy E Taylor, Marcus R Munafò
    International journal of epidemiology. 08/2014;
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    ABSTRACT: Purpose: To compare perceptions of text and pictorial warning labels on cigarette packs among Ghanaian smokers and nonsmokers and explore their views on the introduction of pictorial warnings in Ghana. Methods: Qualitative study involving 12 focus group discussions with 50 smokers and 35 nonsmokers aged 15 and over in Kumasi, Ghana. Semi-structured discussion guides alongside visual discussant aids were used to explore the perception, acceptance, and potential use of pictorial warning labels in Ghana. Results: Health warnings combining text and a picture (pictorial) were perceived by both smokers and nonsmokers to communicate health messages more effectively than text-only or picture-only warnings. The effect of text-only warnings was considered limited by low levels of literacy and those of any health warning on the pack by the common practice of single stick sales. Of the 6 health warnings tested, lung cancer, blindness, stroke, and throat and mouth cancer messages were perceived to have the most impact on smoking behavior, including uptake and quit attempts. Conclusions: Warning labels combining pictures and text have the potential to reduce smoking uptake, increase quit attempts, and reduce smoking appeal among smokers and nonsmokers in Ghana. Measures to prevent single stick sales, or to promote health messages to purchasers of single sticks, are required.
    Nicotine & Tobacco Research 08/2014; · 2.48 Impact Factor
  • Jennifer J. Ware, Marcus R. Munafò
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    ABSTRACT: Background and AimsThe low reproducibility of findings within the scientific literature is a growing concern. This may be due to many findings being false positives which, in turn, can misdirect research effort and waste money.Methods We review factors that may contribute to poor study reproducibility and an excess of ‘significant’ findings within the published literature. Specifically, we consider the influence of current incentive structures and the impact of these on research practices.ResultsThe prevalence of false positives within the literature may be attributable to a number of questionable research practices, ranging from the relatively innocent and minor (e.g. unplanned post-hoc tests) to the calculated and serious (e.g. fabrication of data). These practices may be driven by current incentive structures (e.g. pressure to publish), alongside the preferential emphasis placed by journals on novelty over veracity. There are a number of potential solutions to poor reproducibility, such as new publishing formats that emphasize the research question and study design, rather than the results obtained. This has the potential to minimize significance chasing and non-publication of null findings.Conclusions Significance chasing, questionable research practices and poor study reproducibility are the unfortunate consequence of a ‘publish or perish’ culture and a preference among journals for novel findings. It is likely that top–down change implemented by those with the ability to modify current incentive structure (e.g. funders and journals) will be required to address problems of poor reproducibility.
    Addiction 08/2014; · 4.58 Impact Factor
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    Marcus R. Munafò, Stanley Zammit, Jonathan Flint
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    ABSTRACT: Rutter's commentary (Rutter, 2014) on our article (Munafò et al., 2014) provides us the opportunity to clarify some issues that he (and therefore, we suspect, others) may have misunderstood.
    Journal of Child Psychology and Psychiatry 08/2014; · 5.42 Impact Factor
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    ABSTRACT: Many studies have examined the efficacy of psychotherapy for major depressive disorder (MDD) but publication bias against null results may exist in this literature. However, to date, the presence of an excess of significant findings in this literature has not been explicitly tested.
    Psychological medicine. 07/2014;

Publication Stats

6k Citations
1,634.66 Total Impact Points


  • 2005–2014
    • University of Bristol
      • School of Experimental Psychology
      Bristol, England, United Kingdom
  • 2013
    • National and Kapodistrian University of Athens
      Athínai, Attica, Greece
    • University of Liverpool
      • Department of Psychological Sciences
      Liverpool, England, United Kingdom
    • Universität Regensburg
      Ratisbon, Bavaria, Germany
    • University of Chicago
      • Department of Psychiatry and Behavioral Neuroscience
      Chicago, IL, United States
    • Sungkyunkwan University
      Sŏul, Seoul, South Korea
  • 2008–2013
    • Alpert Medical School - Brown University
      • Department of Family Medicine
      Providence, Rhode Island, United States
    • Memorial Hospital of Rhode Island
      Pawtucket, Rhode Island, United States
    • University of Pennsylvania
      • Department of Psychiatry
      Philadelphia, PA, United States
  • 2001–2013
    • University of Oxford
      • • Wellcome Trust Centre for Human Genetics
      • • Department of Psychiatry
      • • Department of Experimental Psychology
      Oxford, ENG, United Kingdom
  • 2012
    • Cardiff University
      • Department of Psychological Medicine and Neurology
      Cardiff, WLS, United Kingdom
    • University of New South Wales
      • School of Psychology
      Kensington, New South Wales, Australia
    • University of Nottingham
      • Division of Epidemiology and Public Health
      Nottingham, ENG, United Kingdom
  • 2011–2012
    • Edinburgh Napier University
      • School of Life, Sport & Social Sciences
      Edinburgh, SCT, United Kingdom
    • University of Georgia
      • Department of Psychology
      Athens, GA, United States
    • University of Bath
      • Department for Health
      Bath, England, United Kingdom
    • Stanford Medicine
      Stanford, California, United States
  • 2001–2012
    • University of Southampton
      • • Academic Unit of Clinical and Experimental Sciences
      • • Clinical Neurosciences
      Southampton, ENG, United Kingdom
  • 2008–2011
    • University of Cambridge
      • Department of Psychiatry
      Cambridge, ENG, United Kingdom
  • 2007–2011
    • University of Birmingham
      • Department of Primary Care Clinical Sciences
      Birmingham, ENG, United Kingdom
    • Temple University
      • Department of Public Health
      Philadelphia, PA, United States
  • 2010
    • National Institutes of Health
      • Molecular Neurobiology Research Branch
      Bethesda, MD, United States
  • 2007–2008
    • Brown University
      • Centers for Behavioral and Preventive Medicine
      Providence, RI, United States