Ifsttar PhD subject

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Title : Epidemiology of chronic pain after a road traffic accident: the role of emotions and their regulation in the persistence of pain.

Main host Laboratory - Referent Advisor TS2 - UMRESTTE  -  LAFONT Sylviane      tél. : +33 472142517

Director of the main host Laboratory CHARBOTEL-COING-BOYAT barbara  -

PhD Speciality Épidémiologie

Axis of the performance contract 1 - COP2017 - Efficient transport and safe travel

Main location Bron

Doctoral affiliation UNIVERSITE CLAUDE-BERNARD-LYON 1

PhD school ECOLE DOCTORALE INTERDISCIPLINAIRE SCIENCES-SANTE (EDISS)

Planned PhD supervisor LAFONT Sylviane  -  Université Gustave Eiffel  -  TS2 - UMRESTTE

Planned financing Contrat doctoral  - Ifsttar

Abstract

Background information
Pain is "an unpleasant sensation and emotional experience in response to actual or potential tissue damage or described in these terms" according to the International Association for the Study of Pain. It becomes chronic if it persists more than three months after the acute episode, despite therapeutic management, and if it induces functional and relational deterioration. In France, 32% of adults has chronic pain (1) and 15% has chronic pain condition for more than 6 months with an intensity of 5 or more on a scale of 1 to 10 (2). After a road accident, a year later, very many victims still suffer from pain: 64% of those who are slightly and moderately injured, and 85% of those who are seriously injured (3). However, the proportion of chronic pain attributable to a road accident has to be estimated among all chronic pain causes. Chronic pain causes high levels of drug and medical consumption. In the case of road accidents, 39% of serious injuried and 23% of moderate and light injuried still use painkillers one year after the accident (3). Regarding medical consumption, a study shows that 14% of chronic pain patients have visited a doctor once in the last 6 months, 60% between 2 and 9 times, and 11% at least 10 times. Nevertheless, 13% of those who have visited more than once are dissatisfied with the response to treatment, or in failure with their doctor. This last figure can be compared with the health crisis experienced in the United States, and to a lesser extent in France, with the misuse of opioids. Finally, chronic pain affects quality of life, functional abilities and professional life (61% can no longer leave home, 19% have lost their jobs), and increases associated syndromes (e.g. 21% depression attributed to pain) (2). In this general or specific context of road accidents, preventing the chronicisation of acute pain is a very important public health issue.
Often complex and multidimensional, the persistence of pain is nowadays understood with a biopsychosocial approach (4). Biologically, women develop chronic painful conditions more often, and some phenotypes are more at risk (5). The study of fibromyalgia shows that some people have lower pain tolerance thresholds than others (6). The origin of the symptom, duration and severity may also promote the chronicization of pain; a physical cause will be associated with higher levels of perceived pain. Sociologically, an unfavourable social environment can reinforce symptoms and consequences (7).
For the psychological aspects, various factors are sources of vulnerability to chronic pain or, on the contrary, resilience. The meaning given to pain, personal beliefs, the pain assessment process, the personal belief that required behaviours can be successfully adopted in certain situations, are factors that will allow the individual to assume his or her role as a patient or to ignore pain, or to mobilize a significant effort (8). Personality traits (catastrophism, anxiety, depression) can also contribute to the chronicization of pain (5). Concerning the emotional dimension, its link with acute pain is well known: negative emotions exacerbate the perception and feeling of pain and lower its tolerance threshold. (5). The opposite is true for positive emotions, but to a lesser extent. The intensity of the emotion also has an impact on pain: the more intense the emotion is, the stronger is its effect. Rhudy hypothesizes that the failure of emotional pain modulation is a phenotype at risk for pain and emotional disorders.
The relationship between emotions and chronic pain exists (9), but its direction is unclear because the emotional state is measured when the pain is already chronic, which makes it impossible to know, for example, whether sadness promotes the persistence of pain, or whether chronic pain promotes sadness. Beyond emotions, inadequate emotional regulation may increase the chronic pain risk. The particular case of road trauma adds a specific component to these aspects, through the violence of the impact, or through the involvement of others in the accident (feeling victim or responsible). All these psychological mechanisms are complex and often linked. It is proposed to explore in detail the role of emotional state and its regulation on the chronic pain risk after a road traffic accident.

Thesis objectives :
1. Describe the characteristics, risk factors and consequences of chronic pain after a traffic accident.
2. Study the role of emotional state and its regulation in the pain chronicization.
3. Estimate the proportion of chronic pain after a road trauma among all other causes and identify possible specificities.

Methodology
The knowledge contribution on chronic pain after a road accident will be possible thanks to the data of the ESPARR cohort (follow-up study of a population of road accident victims in the Rhône). It contains rich information on the existence of pain at one, two, three and five years after the accident. The number of subjects (1372), the duration of follow-up, and the content of these follow-ups make it a quality tool for this problem. People were asked about many aspects of interest in chronic pain (biological, sociological and psychological) such as the frequency of negative feelings, the use of psychotropic drugs or the measurement of cognitive disorders including the reduction of emotions.
a) 3000 patients included in a clinical trial on the prevention of post-traumatic stress disorder through an EMDR (Eye movement desentization and reprocessing) intervention. This study, led by E Lagarde from Inserm in Bordeaux, is funded by a national PHRC (SOFTER IV). Within the framework of this thesis, the risk of chronic pain will be studied with, as a factor of interest, the emotional state of the person at the entrance and exit of emergencies, and his ability to regulate his emotions. The strong links between stress and pain (5) will be taken into account..
b) 150 patients with simple long bone fracture. As this type of injury and its management generally does not result in chronic pain, it will be possible to isolate the psychological dimension in the chronic pain risk. M. Galinski, an emergency physician specialized in pain who would be co-supervisor of this thesis, is conducting a study on the impact of optimizing pain management in emergency departments on the chronicization risk following a long bone fracture (CHRONODOL). The emotional state as an explanatory factor for the pain chronicization will complete its protocol.

Expected results
This work on the emotional state and the ability to regulate emotions at the time of an acute pain due to trauma will enrich the the biopsychosocial model theory of chronic pain. It will help to diagnose high-risk patients at an early stage and provide them with appropriate care. It will open up new possibilities for intervention based on the regulation of emotions, with a particular focus on the specificities highlighted in road traffic accidents. This will hopefully reduce the negative consequences of road accidents on health, quality of life, family life and working life. The expected benefits are also societal with potential gains on the cost of overall management of chronic pain after a road accident.

1. Bouhassira D, Lantéri-Minet M, Attal N, Laurent B, Touboul C. Prevalence of chronic pain with neuropathic characteristics in the general population. PAIN. 2008 Jun 15;136(3):380–7.
2. Breivik H, Collett B, Ventafridda V, Cohen R, Gallacher D. Survey of chronic pain in Europe: Prevalence, impact on daily life, and treatment. Eur J Pain. 2006 May;10(4):287–287.
3. Hours M, Chossegros L, Charnay P, Tardy H, Nhac-Vu H-T, Boisson D, et al. Outcomes one year after a road accident: Results from the ESPARR cohort. Accid Anal Prev. 2013 Jan;50:92–102.
4. Engel GL. The need for a new medical model: a challenge for biomedicine. Science. 1977 Apr 8;196(4286):129–36.
5. Flaten MA, Absi M al, editors. The neuroscience of pain, stress, and emotion: psychological and clinical implications. Amsterdam: Academic Press is an imprint of Elsevier; 2016. 296 p.
6. Simonnet G, Laurent B, Le Breton D. L’homme douloureux [Internet]. Librairie Eyrolles. Odile Jacob; 2018 [cited 2019 Sep 9]. 304 p. (Médecine). Available from: https://www.eyrolles.com/Sciences/Livre/l-homme-douloureux-9782738145888/
7. Hanley O, Miner J, Rockswold E, Biros M. The relationship between chronic illness, chronic pain, and socioeconomic factors in the ED. Am J Emerg Med. 2011 Mar 1;29(3):286–92.
8. Turk DC, Okifuji A. Psychological factors in chronic pain: Evolution and revolution. J Consult Clin Psychol. 2002 Jun;70(3):678–90.
9. Koechlin H, Coakley R, Schechter N, Werner C, Kossowsky J. The role of emotion regulation in chronic pain: A systematic literature review. J Psychosom Res. 2018 Apr 1;107:38–45.

Keywords : Road accidents; Trauma; Pain chronization; Emotion; Emotional regulation; Stress

Main host Laboratory - Referent Advisor	TS2 - UMRESTTE - LAFONT Sylviane tél. : +33 472142517
Director of the main host Laboratory	CHARBOTEL-COING-BOYAT barbara -
PhD Speciality	Épidémiologie
Axis of the performance contract	1 - COP2017 - Efficient transport and safe travel
Main location	Bron
Doctoral affiliation	UNIVERSITE CLAUDE-BERNARD-LYON 1
PhD school	ECOLE DOCTORALE INTERDISCIPLINAIRE SCIENCES-SANTE (EDISS)
Planned PhD supervisor	LAFONT Sylviane - Université Gustave Eiffel - TS2 - UMRESTTE
Planned financing	Contrat doctoral - Ifsttar
Abstract Background information Pain is "an unpleasant sensation and emotional experience in response to actual or potential tissue damage or described in these terms" according to the International Association for the Study of Pain. It becomes chronic if it persists more than three months after the acute episode, despite therapeutic management, and if it induces functional and relational deterioration. In France, 32% of adults has chronic pain (1) and 15% has chronic pain condition for more than 6 months with an intensity of 5 or more on a scale of 1 to 10 (2). After a road accident, a year later, very many victims still suffer from pain: 64% of those who are slightly and moderately injured, and 85% of those who are seriously injured (3). However, the proportion of chronic pain attributable to a road accident has to be estimated among all chronic pain causes. Chronic pain causes high levels of drug and medical consumption. In the case of road accidents, 39% of serious injuried and 23% of moderate and light injuried still use painkillers one year after the accident (3). Regarding medical consumption, a study shows that 14% of chronic pain patients have visited a doctor once in the last 6 months, 60% between 2 and 9 times, and 11% at least 10 times. Nevertheless, 13% of those who have visited more than once are dissatisfied with the response to treatment, or in failure with their doctor. This last figure can be compared with the health crisis experienced in the United States, and to a lesser extent in France, with the misuse of opioids. Finally, chronic pain affects quality of life, functional abilities and professional life (61% can no longer leave home, 19% have lost their jobs), and increases associated syndromes (e.g. 21% depression attributed to pain) (2). In this general or specific context of road accidents, preventing the chronicisation of acute pain is a very important public health issue. Often complex and multidimensional, the persistence of pain is nowadays understood with a biopsychosocial approach (4). Biologically, women develop chronic painful conditions more often, and some phenotypes are more at risk (5). The study of fibromyalgia shows that some people have lower pain tolerance thresholds than others (6). The origin of the symptom, duration and severity may also promote the chronicization of pain; a physical cause will be associated with higher levels of perceived pain. Sociologically, an unfavourable social environment can reinforce symptoms and consequences (7). For the psychological aspects, various factors are sources of vulnerability to chronic pain or, on the contrary, resilience. The meaning given to pain, personal beliefs, the pain assessment process, the personal belief that required behaviours can be successfully adopted in certain situations, are factors that will allow the individual to assume his or her role as a patient or to ignore pain, or to mobilize a significant effort (8). Personality traits (catastrophism, anxiety, depression) can also contribute to the chronicization of pain (5). Concerning the emotional dimension, its link with acute pain is well known: negative emotions exacerbate the perception and feeling of pain and lower its tolerance threshold. (5). The opposite is true for positive emotions, but to a lesser extent. The intensity of the emotion also has an impact on pain: the more intense the emotion is, the stronger is its effect. Rhudy hypothesizes that the failure of emotional pain modulation is a phenotype at risk for pain and emotional disorders. The relationship between emotions and chronic pain exists (9), but its direction is unclear because the emotional state is measured when the pain is already chronic, which makes it impossible to know, for example, whether sadness promotes the persistence of pain, or whether chronic pain promotes sadness. Beyond emotions, inadequate emotional regulation may increase the chronic pain risk. The particular case of road trauma adds a specific component to these aspects, through the violence of the impact, or through the involvement of others in the accident (feeling victim or responsible). All these psychological mechanisms are complex and often linked. It is proposed to explore in detail the role of emotional state and its regulation on the chronic pain risk after a road traffic accident. Thesis objectives : 1. Describe the characteristics, risk factors and consequences of chronic pain after a traffic accident. 2. Study the role of emotional state and its regulation in the pain chronicization. 3. Estimate the proportion of chronic pain after a road trauma among all other causes and identify possible specificities. Methodology The knowledge contribution on chronic pain after a road accident will be possible thanks to the data of the ESPARR cohort (follow-up study of a population of road accident victims in the Rhône). It contains rich information on the existence of pain at one, two, three and five years after the accident. The number of subjects (1372), the duration of follow-up, and the content of these follow-ups make it a quality tool for this problem. People were asked about many aspects of interest in chronic pain (biological, sociological and psychological) such as the frequency of negative feelings, the use of psychotropic drugs or the measurement of cognitive disorders including the reduction of emotions. a) 3000 patients included in a clinical trial on the prevention of post-traumatic stress disorder through an EMDR (Eye movement desentization and reprocessing) intervention. This study, led by E Lagarde from Inserm in Bordeaux, is funded by a national PHRC (SOFTER IV). Within the framework of this thesis, the risk of chronic pain will be studied with, as a factor of interest, the emotional state of the person at the entrance and exit of emergencies, and his ability to regulate his emotions. The strong links between stress and pain (5) will be taken into account.. b) 150 patients with simple long bone fracture. As this type of injury and its management generally does not result in chronic pain, it will be possible to isolate the psychological dimension in the chronic pain risk. M. Galinski, an emergency physician specialized in pain who would be co-supervisor of this thesis, is conducting a study on the impact of optimizing pain management in emergency departments on the chronicization risk following a long bone fracture (CHRONODOL). The emotional state as an explanatory factor for the pain chronicization will complete its protocol. Expected results This work on the emotional state and the ability to regulate emotions at the time of an acute pain due to trauma will enrich the the biopsychosocial model theory of chronic pain. It will help to diagnose high-risk patients at an early stage and provide them with appropriate care. It will open up new possibilities for intervention based on the regulation of emotions, with a particular focus on the specificities highlighted in road traffic accidents. This will hopefully reduce the negative consequences of road accidents on health, quality of life, family life and working life. The expected benefits are also societal with potential gains on the cost of overall management of chronic pain after a road accident. 1. Bouhassira D, Lantéri-Minet M, Attal N, Laurent B, Touboul C. Prevalence of chronic pain with neuropathic characteristics in the general population. PAIN. 2008 Jun 15;136(3):380–7. 2. Breivik H, Collett B, Ventafridda V, Cohen R, Gallacher D. Survey of chronic pain in Europe: Prevalence, impact on daily life, and treatment. Eur J Pain. 2006 May;10(4):287–287. 3. Hours M, Chossegros L, Charnay P, Tardy H, Nhac-Vu H-T, Boisson D, et al. Outcomes one year after a road accident: Results from the ESPARR cohort. Accid Anal Prev. 2013 Jan;50:92–102. 4. Engel GL. The need for a new medical model: a challenge for biomedicine. Science. 1977 Apr 8;196(4286):129–36. 5. Flaten MA, Absi M al, editors. The neuroscience of pain, stress, and emotion: psychological and clinical implications. Amsterdam: Academic Press is an imprint of Elsevier; 2016. 296 p. 6. Simonnet G, Laurent B, Le Breton D. L’homme douloureux [Internet]. Librairie Eyrolles. Odile Jacob; 2018 [cited 2019 Sep 9]. 304 p. (Médecine). Available from: https://www.eyrolles.com/Sciences/Livre/l-homme-douloureux-9782738145888/ 7. Hanley O, Miner J, Rockswold E, Biros M. The relationship between chronic illness, chronic pain, and socioeconomic factors in the ED. Am J Emerg Med. 2011 Mar 1;29(3):286–92. 8. Turk DC, Okifuji A. Psychological factors in chronic pain: Evolution and revolution. J Consult Clin Psychol. 2002 Jun;70(3):678–90. 9. Koechlin H, Coakley R, Schechter N, Werner C, Kossowsky J. The role of emotion regulation in chronic pain: A systematic literature review. J Psychosom Res. 2018 Apr 1;107:38–45.
Keywords :	Road accidents; Trauma; Pain chronization; Emotion; Emotional regulation; Stress

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