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Review
Stress and functional neurological disorders: mechanistic insights
  1. Roxanne C Keynejad1,
  2. Thomas Frodl2,
  3. Richard Kanaan3,4,5,
  4. Carmine Pariante6,
  5. Markus Reuber7,
  6. Timothy R Nicholson8
  1. 1 Section of Women’s Mental Health, Health Service and Population Research Department, Institute of Psychiatry Psychology & Neuroscience, King’s College London, London, UK
  2. 2 Department and Hospital of Psychiatry and Psychotherapy, Otto von Guericke University Magdeburg, Magdeburg, Germany
  3. 3 Section of Cognitive Neuropsychiatry, Institute of Psychiatry Psychology & Neuroscience, King’s College London, UK, London
  4. 4 Department of Psychiatry, University of Melbourne, Austin Health, Austin, Heidelberg, Australia
  5. 5 Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia
  6. 6 Stress Psychiatry and Immunology Lab, Institute of Psychiatry Psychology & Neuroscience, King’s College London, London, UK
  7. 7 Academic Neurology Unit, University of Sheffield, Royal Hallamshire Hospital, Sheffield, UK
  8. 8 Section of Cognitive Neuropsychiatry, Institute of Psychiatry Psychology & Neuroscience, King’s College London, London, UK
  1. Correspondence to Dr Roxanne C Keynejad, Section of Women’s Mental Health, Health Service and Population Research Department, Institute of Psychiatry Psychology & Neuroscience, King’s College London, London SE5 8AF, UK; roxanne.keynejad{at}kcl.ac.uk

Abstract

At the interface between mind and body, psychiatry and neurology, functional neurological disorder (FND) remains poorly understood. Formerly dominant stress-related aetiological models have been increasingly challenged, in part due to cases without any history of past or recent trauma. In this perspective article, we review current evidence for such models, and how research into the role of traumatic stress in other disorders and the neurobiology of the stress response can inform our mechanistic understanding of FND. First, we discuss the association between stress and the onset or exacerbation of a variety of physical and mental health problems. Second, we review the role of hypothalamic-pituitary-adrenal axis dysfunction in the neurobiology of ill-health, alongside evidence for similar mechanisms in FND. Third, we advocate a stress-diathesis model, in which biological susceptibility interacts with early life adversity, where FND can be precipitated by traumatic events later in life and maintained by psychological responses. We hypothesise that greater biological susceptibility to FND is associated with less severe remote and recent stress, and that FND precipitated by more severe stress is associated with lower biological vulnerability. This would explain clinical experience of variable exposure to historical and recent traumatic stress among people with FND and requires empirical investigation. A testable, evidence-based stress-diathesis model can inform nuanced understanding of how biological and psychological factors interact at the individual level, with potential to inform personalised treatment pathways. Much-needed research to establish the aetiology of FND will enhance clinical care and communication, facilitate effective treatment and inform prevention strategies.

  • functional neurological disorder
  • conversion disorder
  • neuropsychiatry
  • trauma, psychol seque
  • stress

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Footnotes

  • Contributors RCK wrote the first draft of this review and led the writing and coordination of subsequent edits. TF, RK, CP and MR reviewed drafts,provided comments, edits and amendments leading to the final submission. TRN supervised the writing of this review from its inception, coauthored the first draft and edited subsequent drafts leading to the final submission.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent Not required.

  • Provenance and peer review Commissioned; externally peer reviewed.

  • Data sharing statement No original data are presented in this review.

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