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Dr Marc Williams
- Welsh speaking
Teams and roles for Marc Williams
Senior Academic Tutor / Honorary Senior Lecturer
Overview
Dr Williams is a Clinical Psychologist within the NHS, with clinical and research expertise in eating disorders. He is co-chair of the Division of Clinical Psychology's Planetary Health Subgroup, which explores ways to embed environmental awareness and sustainability into curricula, preparing future psychologists to address the mental health impacts of planetary health challenges.
At Cardiff University, Dr Williams teaches on two Psychology Master's Programmes and is actively involved in the academic community as a member of the University Research Ethics Committee and the Equity and Representation Subcommittee on the south Wales Clinical Psychology Programme. Dr Williams is Co-Editor-in-Chief of Psychology and Psychotherapy: Theory, Research and Practice.
Dr Williams is available to provide research supervision in both Welsh and English on topics related to eating disorders, the psychological impacts of climate change, and sustainable practices in clinical psychology.
Publication
2025
- Morey, A. et al. 2025. Validation of the comprehensive assessment of acceptance and commitment therapy processes for youth: The CompACT‐Y. JCPP Advances 5 (2) e12271. (10.1002/jcv2.12271)
- Ramsay, G. et al., 2025. A COSMIN systematic review of the psychometric properties of instruments that measure climate change-related distress. Cogent Mental Health 4 (1), pp.1-27. (10.1080/28324765.2025.2449878)
- Roberts, A. , Poortinga, W. and Williams, M. O. 2025. Climate anxiety in the United Kingdom: Associations with environmentally relevant behavioural intentions, and the moderating role of efficacy. Journal of Environmental Psychology 105 102595. (10.1016/j.jenvp.2025.102595)
- Thomas, K. S. et al. 2025. Neural correlates of emotion regulation and associations with disordered eating during preadolescence. Developmental Psychobiology 67 (1) e70009. (10.1002/dev.70009)
2024
- Calabria, L. , Peters, C. and Williams, M. 2024. Compassion-focused approaches to understanding the mental health of climate scientists. The Cognitive Behaviour Therapist 17 e34. (10.1017/S1754470X23000223)
- Field, S. L. et al. 2024. A meta-ethnography of autistic people’s experiences of social camouflaging and its relationship with mental health. Autism 28 (6), pp.1328-1343. (10.1177/13623613231223036)
- Finch, K. et al. 2024. Relationships between adverse childhood experiences, attachment, resilience, psychological distress and trauma among forensic mental health populations. The Journal of Forensic Psychiatry & Psychology 35 (5), pp.660-684. (10.1080/14789949.2024.2365149)
- Marffy, M. , Fox, J. and Williams, M. 2024. An exploration of the relationship between loneliness, the severity of eating disorder-related symptoms and the experience of the 'anorexic voice'. Psychology and Psychotherapy: Theory, Research and Practice 97 (1), pp.122-137. (10.1111/papt.12502)
- Morey, A. , Samuel, V. and Williams, M. 2024. Universal online self-help ACT interventions for youth: A systematic review. Behaviour Research and Therapy 180 104576. (10.1016/j.brat.2024.104576)
- Thomas, K. S. et al. 2024. Associations between disordered eating, internalizing symptoms, and behavioral and neural correlates of response inhibition in preadolescence. Developmental Psychobiology 66 (3) e22477. (10.1002/dev.22477)
- Williams, M. and Samuel, V. 2024. Acceptance and commitment therapy as an approach for working with climate distress. The Cognitive Behaviour Therapist 17 e35. (10.1017/S1754470X23000247)
- Williams, M. O. et al. 2024. Climate anxiety and its association with health behaviours and generalized anxiety: An intensive longitudinal study. British Journal of Health Psychology 29 (4), pp.1080-1095. (10.1111/bjhp.12746)
- Williams, M. O. et al. 2024. ‘There’s no helpline’: how mental health services can support young people with climate distress. Cogent Mental Health 3 (1) 2409815. (10.1080/28324765.2024.2409815)
2023
- Field, S. L. et al. 2023. “Work WITH us”: a Delphi study about improving eating disorder treatment for autistic women with anorexia nervosa. Journal of Eating Disorders 11 (1) 17. (10.1186/s40337-023-00740-z)
- Howard, T. L. M. et al. 2023. The relationship between shame, perfectionism and Anorexia Nervosa: a grounded theory study. Psychology and Psychotherapy: Theory, Research and Practice 96 (1), pp.40-55. (10.1111/papt.12425)
- Rea, S. et al. 2023. Role of psychological flexibility and self-compassion in people on home parenteral nutrition: psychological, line care adherence and infection outcomes. Mediterranean Journal of Clinical Psychology 11 (2)(10.13129/2282-1619/mjcp-3696)
- Williams, M. 2023. A mixed-methods examination of nature beliefs as predictors of sustainable behaviour in the UK/Archwiliad dulliau cymysg o gredoau natur sy’n darogan ymddygiad cynaliadwy yn y DU. PhD Thesis , Cardiff University.
- Williams, M. et al. 2023. Croedau am werth cynhenid a pherthynol byd natur: Sut maent yn cydberthyn ag ymddygiad cynaliadwy yn y Dernas Unedig?. Gwerddon (35)
- Williams, M. O. 2023. Climate distress and social identity: Bringing theory to clinical practice. Frontiers in Psychology 14 1126922. (10.3389/fpsyg.2023.1126922)
2022
- Finch, K. et al. 2022. A systematic review of the effectiveness of safewards: Has enthusiasm exceeded evidence?. Issues in Mental Health Nursing 43 (2), pp.119-136. (10.1080/01612840.2021.1967533)
- Morrison, J. , Williams, M. O. and Fox, J. R. E. 2022. Negative childhood events and the development of the anorexic voice: A grounded theory. Psychology and Psychotherapy: Theory, Research and Practice 95 (4), pp.1018-1035. (10.1111/papt.12416)
- Whitmarsh, L. et al. 2022. Climate anxiety: What predicts it and how is it related to climate action?. Journal of Environmental Psychology 83 101866. (10.1016/j.jenvp.2022.101866)
2021
- Stott, N. , Williams, M. and Fox, J. 2021. Attentional bias in eating disorders: a meta-review. International Journal of Eating Disorders 54 (8), pp.1377-1399. (10.1002/eat.23560)
- Thomas, K. S. , Williams, M. O. and Vanderwert, R. E. 2021. Disordered eating and internalizing symptoms in preadolescence. Brain and Behavior 11 (1) e01904. (10.1002/brb3.1904)
- Williams, M. , Whitmarsh, L. and Chríost, D. M. G. 2021. The association between anthropomorphism of nature and pro-environmental variables: a systematic review. Biological Conservation 255 109022. (10.1016/j.biocon.2021.109022)
- Williams, M. O. et al. 2021. A grounded theory of pro-nature behaviour: from moral concern to sustained action. Sustainability 13 (16) 8944. (10.3390/su13168944)
2020
- Williams, M. 2020. The relationship between climate change and mental health information-seeking: a preliminary investigation. Journal of Public Mental Health 20 , pp.69-78. (10.1108/JPMH-04-2020-0025)
2017
- Williams, M. O. et al. 2017. Compassion-focused therapy for bulimia nervosa and bulimic presentations: a preliminary case series. Behaviour Change 34 (3), pp.199-207. (10.1017/bec.2017.13)
2014
- Williams, M. , Mathews, A. and Hirsch, C. R. 2014. Verbal worry facilitates attention to threat in high-worriers. Journal of Behavior Therapy and Experimental Psychiatry 45 (1), pp.8-14. (10.1016/j.jbtep.2013.05.006)
Articles
- Calabria, L. , Peters, C. and Williams, M. 2024. Compassion-focused approaches to understanding the mental health of climate scientists. The Cognitive Behaviour Therapist 17 e34. (10.1017/S1754470X23000223)
- Field, S. L. et al. 2023. “Work WITH us”: a Delphi study about improving eating disorder treatment for autistic women with anorexia nervosa. Journal of Eating Disorders 11 (1) 17. (10.1186/s40337-023-00740-z)
- Field, S. L. et al. 2024. A meta-ethnography of autistic people’s experiences of social camouflaging and its relationship with mental health. Autism 28 (6), pp.1328-1343. (10.1177/13623613231223036)
- Finch, K. et al. 2022. A systematic review of the effectiveness of safewards: Has enthusiasm exceeded evidence?. Issues in Mental Health Nursing 43 (2), pp.119-136. (10.1080/01612840.2021.1967533)
- Finch, K. et al. 2024. Relationships between adverse childhood experiences, attachment, resilience, psychological distress and trauma among forensic mental health populations. The Journal of Forensic Psychiatry & Psychology 35 (5), pp.660-684. (10.1080/14789949.2024.2365149)
- Howard, T. L. M. et al. 2023. The relationship between shame, perfectionism and Anorexia Nervosa: a grounded theory study. Psychology and Psychotherapy: Theory, Research and Practice 96 (1), pp.40-55. (10.1111/papt.12425)
- Marffy, M. , Fox, J. and Williams, M. 2024. An exploration of the relationship between loneliness, the severity of eating disorder-related symptoms and the experience of the 'anorexic voice'. Psychology and Psychotherapy: Theory, Research and Practice 97 (1), pp.122-137. (10.1111/papt.12502)
- Morey, A. et al. 2025. Validation of the comprehensive assessment of acceptance and commitment therapy processes for youth: The CompACT‐Y. JCPP Advances 5 (2) e12271. (10.1002/jcv2.12271)
- Morey, A. , Samuel, V. and Williams, M. 2024. Universal online self-help ACT interventions for youth: A systematic review. Behaviour Research and Therapy 180 104576. (10.1016/j.brat.2024.104576)
- Morrison, J. , Williams, M. O. and Fox, J. R. E. 2022. Negative childhood events and the development of the anorexic voice: A grounded theory. Psychology and Psychotherapy: Theory, Research and Practice 95 (4), pp.1018-1035. (10.1111/papt.12416)
- Ramsay, G. et al., 2025. A COSMIN systematic review of the psychometric properties of instruments that measure climate change-related distress. Cogent Mental Health 4 (1), pp.1-27. (10.1080/28324765.2025.2449878)
- Rea, S. et al. 2023. Role of psychological flexibility and self-compassion in people on home parenteral nutrition: psychological, line care adherence and infection outcomes. Mediterranean Journal of Clinical Psychology 11 (2)(10.13129/2282-1619/mjcp-3696)
- Roberts, A. , Poortinga, W. and Williams, M. O. 2025. Climate anxiety in the United Kingdom: Associations with environmentally relevant behavioural intentions, and the moderating role of efficacy. Journal of Environmental Psychology 105 102595. (10.1016/j.jenvp.2025.102595)
- Stott, N. , Williams, M. and Fox, J. 2021. Attentional bias in eating disorders: a meta-review. International Journal of Eating Disorders 54 (8), pp.1377-1399. (10.1002/eat.23560)
- Thomas, K. S. et al. 2025. Neural correlates of emotion regulation and associations with disordered eating during preadolescence. Developmental Psychobiology 67 (1) e70009. (10.1002/dev.70009)
- Thomas, K. S. et al. 2024. Associations between disordered eating, internalizing symptoms, and behavioral and neural correlates of response inhibition in preadolescence. Developmental Psychobiology 66 (3) e22477. (10.1002/dev.22477)
- Thomas, K. S. , Williams, M. O. and Vanderwert, R. E. 2021. Disordered eating and internalizing symptoms in preadolescence. Brain and Behavior 11 (1) e01904. (10.1002/brb3.1904)
- Whitmarsh, L. et al. 2022. Climate anxiety: What predicts it and how is it related to climate action?. Journal of Environmental Psychology 83 101866. (10.1016/j.jenvp.2022.101866)
- Williams, M. 2020. The relationship between climate change and mental health information-seeking: a preliminary investigation. Journal of Public Mental Health 20 , pp.69-78. (10.1108/JPMH-04-2020-0025)
- Williams, M. , Mathews, A. and Hirsch, C. R. 2014. Verbal worry facilitates attention to threat in high-worriers. Journal of Behavior Therapy and Experimental Psychiatry 45 (1), pp.8-14. (10.1016/j.jbtep.2013.05.006)
- Williams, M. and Samuel, V. 2024. Acceptance and commitment therapy as an approach for working with climate distress. The Cognitive Behaviour Therapist 17 e35. (10.1017/S1754470X23000247)
- Williams, M. , Whitmarsh, L. and Chríost, D. M. G. 2021. The association between anthropomorphism of nature and pro-environmental variables: a systematic review. Biological Conservation 255 109022. (10.1016/j.biocon.2021.109022)
- Williams, M. et al. 2023. Croedau am werth cynhenid a pherthynol byd natur: Sut maent yn cydberthyn ag ymddygiad cynaliadwy yn y Dernas Unedig?. Gwerddon (35)
- Williams, M. O. 2023. Climate distress and social identity: Bringing theory to clinical practice. Frontiers in Psychology 14 1126922. (10.3389/fpsyg.2023.1126922)
- Williams, M. O. et al. 2024. Climate anxiety and its association with health behaviours and generalized anxiety: An intensive longitudinal study. British Journal of Health Psychology 29 (4), pp.1080-1095. (10.1111/bjhp.12746)
- Williams, M. O. et al. 2024. ‘There’s no helpline’: how mental health services can support young people with climate distress. Cogent Mental Health 3 (1) 2409815. (10.1080/28324765.2024.2409815)
- Williams, M. O. et al. 2017. Compassion-focused therapy for bulimia nervosa and bulimic presentations: a preliminary case series. Behaviour Change 34 (3), pp.199-207. (10.1017/bec.2017.13)
- Williams, M. O. et al. 2021. A grounded theory of pro-nature behaviour: from moral concern to sustained action. Sustainability 13 (16) 8944. (10.3390/su13168944)
Thesis
Research
Mae fy niddordebau ymchwil yn cynnwys anhwylderau bwyta a deall perthynas pobl â'u hamgylchedd, yn enwedig o ran effaith newid hinsawdd a cholli bioamrywiaeth.
My research interests include eating disorders and understanding people's relationship with their environment, especially with respect to the impact of climate change and biodiversity loss.
Biography
Undergraduate education
2004-2007: BA(Hons) Experimental Psychology, Oxford University (First Class)
Postgraduate education
2009-2012: Doctorate in Clinical Psychology, King's College London
2018-2023: PhD, Psychology, Cardiff University
Employment
2023-present Clinical Psychologist, Service for High Risk Eating Disorders (SHED), Cardiff & Vale UHB
2022-present Lecturer, Cardiff University
2017-present Senior Tutor, South Wales Doctoral Programme in Clinical Psychology, Cardiff University
2017-2020 Clinical Psychologist, Intestinal Failure Service, Cardiff and Vale University Health Board
2013-2017 Clinical Psychologist, Salford Eating Disorder Service, Greater Manchester West NHS Foundation Trust
2013-2013 Clinical Psychologist, Lighthouse Healthcare, Welshpool
2009-2012 Trainee Clinical Psychologist, South London & Maudsley NHS Foundation Trust
2008-2009 Assistant Psychologist, St Mary's Hospital, Imperial College Healthcare NHS Trust
2007-2008 Assistant Psychologist, Bronglais Hospital, Pembrokeshire and Derwen NHS Trust