Peter completed his undergraduate degree in psychology at Memorial University of Newfoundland. He was awarded a Lord Rothermere Fellowship and qualified as a clinical psychologist in 2000 from the Institute of Psychiatry, King's College, London. He completed his PhD at the Tizard Centre, University of Kent as an NIHR Research Fellow. He then completed an NIHR funded postdoctoral fellowship. He is a Fellow of the British Psychological Society and was awarded the International Association for the Scientific Study of Intellectual and Developmental Disabilities (IASSIDD) Distinguished Achievement Award for Research in 2022. He is serving as a member of the Board of Directors of IASSIDD from 2024 to 2026.  He became a IASSIDD Fellow in 2024. 

He has worked within secure mental healthcare with offenders with intellectual and developmental disabilities for over twenty-five years. His research interests fall broadly within the area of developmental psychology and include the adaptation and evaluation of psychological therapies for people with intellectual and developmental disabilities. He is a non-medical approved clinician as defined with the Mental Health Act. He is registered as both a clinical and forensic psychologist, and is Honorary Associate Director of Research for Herefordshire and Worcestershire Health and Care NHS Trust.  Peter has supervised numerous clinical psychology trainees and PhD students and would welcome approaches from potential students and trainees.

Peter is also the co-convenor of RADiANT (ReseArch in DevelopmentAl NeuropsychiaTry) together with Professor Regi Alexander, Hertfordshire Partnership University NHS Foundation Trust. RADiANT is a consortium of NHS service providers which works in collaboration with academics in a number of universities. It seeks advice from service users, patients, families, charities, community leaders and a range of statutory bodies and organisations. RADiANT focuses on mental health and behavioural issues associated with five developmental conditions- Intellectual Disability (ID), Autistic Spectrum Disorders (ASD), Attention Deficit Hyperactivity Disorder (ADHD), Epilepsy (EPI) and Acquired Brain Injury (ABI). It is hosted by Hertfordshire Partnership University NHS Foundation Trust (HPFT).

Peter has completed a variety of funded research projects involving people with intellectual and other developmental disabilities. These include a randomised control trial of group cognitive behavioural therapy for people with Asperger Syndrome and high functioning autism who also have problems with anxiety (PAsSA Trial), and more recently, and together with colleagues, an HTA funded randomised control trial of EMDR for people with intellectual disabilities (Trauma-AID), and an HTA funded randomised control trial of sertraline for the treatment of anxiety disorders in autistic adults (STRATA), as well as an NIHR funded study examining hospital care pathways for adults with autism detained in hospital (mATCH Study).  He recently secured funding from National Institute for Health and Care Research (NIHR) to investigated the effectiveness of Care (Education) and Treatment Reviews in the NHS in England for children and adults with intellectual disabilities and autistic children and adults. 

Recent Grants

National Institute for Health and Care Research - Health Technology Assessment, 2026 to 2030.  A multicentre two-arm single-blind parallel superiority randomised controlled trial comparing a behavioural intervention for anxiety disorders and treatment-as-usual to treatment-as-usual with adults with modreate to severe intellectual disabilities (BEAMs-ID Trial).  £2,258,740.84. Chief Investigator: Professor Peter Langdon.

Canadian Institutes for Health Research. Empowering youth with intellectual disabilities: co-design and feasability of therapeutic photography for mental health, 2026 to 2031. C$730,576.00.  Chief Investigator: Professor Jonathan A. Weiss.  Co-applicant: Professor Peter Langdon

National Institute for Health and Care Research – Health Technology Assessment, 2026 to 2031.  Development and evaluation of adapted cognitive behaviour therapy for social anxiety in autistic adults: a cluster randomised controlled trial.  £3,583,233.61.  Chief Investigator: Professor Ailsa Russell. Co-applicant: Professor Peter Langdon.

National Institute for Health and Care Research - Health Services and Delivery Research, 2024 to 2027. An evaluation of Care (EduCatIon) and treatment revIews for people with Learning dIsabilities and Autistic people (CECILIA). £1447406.98. Chief Investigators:  Professor Peter Langdon and Professor Karen Bunning.

National Institute for Health and Care Research - Health and Social Care Delivery Research, 2023-2026. High-quality Mental Capacity Act Assessments for Everyone: Improving Leadership, Assessment Procedures, and Patient Support (HELPS). £912,739.52. Chief Investigator: Professor Domenico Giacco. Co-applicant: Professor Peter Langdon.

Social Sciences and Humanities Research Council of Canada. New Frontiers in Research Fund, Special Call, 2023-2025. Mobilising environments to improve psychological and physiological experiences of thriving in autistic people.$484172. Chief Investigator: Dr Jonathan Weiss. Co-applicant: Professor Peter Langdon

National Institute for Health and Care Research - Research for Social Care, 2023 to 2025.  BRIDGING – Breakthrough interview extended reality training towards reducing the autism employment gap.  £339149. Chief Investigator:  Dr Michael Loizou. Co-applicant: Professor Peter Langdon.

National Institute for Health and Care Research - Health Technology Assessment, 2023 to 2024. Medication support interventions and strategies for people with learning disabilities - a mixed methods evidence synthesis. £318545. Chief Investigator: Dr Yen-Fu Chen. Co-applicant: Professor Peter Langdon.

Youth Endowment Fund, 2023 to 2026 - Standard Teen Triple P for parents/carers of 11-15 year olds at the edge-of-care: a randomised controlled trial. £530116. Chief Investigators: Professor Kylie Gray and Dr Paul Thompson. Co-applicant: Professor Peter Langdon.

National Institute for Health and Care Research - Health and Social Care Delivery Research, 2023 to 2025. Digital health participation of people with intellectual disabilities: a longitudinal modelling and digital diary study.  £648288. Chief Investigator: Dr Darren Chadwick. Co-applicant: Professor Peter Langdon.

Youth Endowment Fund, 2022 to 2025 - A randomised controlled trial of brief solution focused Therapy with 10-17-year-olds presenting at policy custody: the Solutions Trial. £828414. Chief Investigators: Dr Sam Flynn and Professor Peter Langdon

National Institute for Health and Care Research- Health Technology Assessment, 2021 to 2025. Guided self-help for depression in adults with autism spectrum disorders (ADEPT-2). £1,675,292. Chief Investigator: Dr Ailsa Russell. Co-applicant: Professor Peter Langdon.

National Institute for Health and Care Research - Health Technology Assessment, 2021 to 2025. A randomised control trial of group cognitive behavioural therapy for men with intellectual and/or developmental disabilities and harmful sexual behaviour. £1,545,849. Chief Investigator: Professor Glynis Murphy. Co-applicant: Professor Peter Langdon.

National Institute for Health and Care Research - Health Technology Assessment. Behavioural interventions to treat anxiety in adults with autism with moderate to severe intellectual disabilities (BEAMS-ID). Chief Investigator: Professor Peter Langdon. £197341.71.

National Institute for Health and Care Research - Health Technology Assessment, 2020 to 2022. Specific phobias in children with learning disabilities (SPIRIT): An adaptation and feasibility study. Chief Investigator: Professor Kylie Gray. Co-applicant: Professor Peter Langdon. £199992.90.

National Institute for Health and Care Research - Health Services and Delivery Research. Mapping and evaluating services for children with learning disabilities and behaviours that challenge (MELD). Chief Investigator: Professor Richard Hastings. Co-Applicant: Professor Peter Langdon £1,245,271.00

Youth Endowment Fund, 2019 to 2022 - REducing the risk of criminal exploitation using multi-SystEmic Therapy (RESET Study). Chief Investigator: Professor Peter Langdon. £299728.00

National Institute for Health and Care Research - Health Technology Assessment, 2019 to 2021- A multicentre double-blind placebo-controlled randomised trial of SerTRaline for AnxieTy in adults with Autism (STRATA) Chief Investigator: Dr Dheeraj Rai. Co-Applicant: Professor Peter Langdon. £1,669,262.68 (+ AUD $557,029.40 by NHMRC Australia to Leonard H, Starkstein S & Glasson E for Perth centre)

National Institute for Health and Care Research - Health Technology Assessment, 2019-2022 - Eye movement desensitisation and reprocessing for symptoms of post-traumatic stress disorder in adults with intellectual disabilities (Trauma-AID). Chief Investigator: Professor Peter Langdon £1,258,097.68.

National Institute for Health and Care Research - Research for Patient Benefit, 2019-2022 - Making positive moves: What support do people with Learning Disabilities need to remain living in the community after moving under the Transforming Care Programme. A qualitative longitudinal study. Chief Investigator: Dr Louisa Roades. Co-Applicant: Professor Peter Langdon. £350,000.

Nuffield Foundation - 2018 to 2021- Development of an assent-based process for the inclusion of adults with impairments of capacity and/or communication in ethically sound research. Chief Investigator: Dr Karen Bunning. Co-Applicant: Professor Peter Langdon. £378,204

National Institute for Health and Care Research - Health Service and Delivery Research, 2017 to 2020 - Clinical and cost effectiveness of intensive support teams for adults with intellectual disabilities and challenging behaviour. Chief Investigator: Professor Angela Hassiotis. Co-applicant: Professor Peter Langdon. £763,483.97

National Institute for Health and Care Research - Research for Patient Benefit, 2015-2018. People with autism detained within hospitals: defining the population, understanding aetiology, and improving care pathways. Chief Investigator: Professor Peter Langdon. £350,000.00