Les principaux objectifs de ce mémoire doctoral sont, à l’aide d’une revue systématique et d’une méta-analyse, de : 1) estimer de façon précise le taux de TSPT après un TCC chez les civils et chez les militaires, 2) vérifier si les groupes avec un TCC ont un plus grand risque de développer un TSPT que ceux exposés à des blessures psychologiques
et physiques similaires mais sans TCC, et 3) vérifier si les populations militaires ont un plus grand risque de développer un TPST après un TCC que les populations civiles.
Un objectif secondaire vise à évaluer l’impact modérateur de facteurs méthodologiques (c’est-à-dire, outils diagnostiques utilisés pour le TSPT et le TCC, groupe de comparaison, qualité des études, devis de la recherche, objectifs de l’étude et taille de l’échantillon) et d’autres facteurs potentiels (c’est-à-dire, temps depuis la blessure, type d’évènement traumatique, sévérité du TCC, pays où a été menée la recherche, sexe et âge moyen des participants) sur la fréquence du TSPT après un TCC.
La méta-analyse permettant de répondre à ces objectifs est présentée au chapitre 1 dans les pages qui suivent.
Chapitre I : A Systematic Review and Meta-Analysis on PTSD
Following TBI Among Military/Veteran and Civilian
Populations
Authors: Alexandra Loignon1, MSc; Marie-Christine Ouellet1,2, PhD; and Geneviève Belleville1, PhD
Author affiliations: 1École de Psychologie, Université Laval, Quebec, QC, Canada; 2Centre interdisciplinaire de recherche en réadaptation et intégration sociale, Quebec, QC, Canada The authors would like to acknowledge the work of Marie-Pier Gaboury and Laura Thériault for their assistance with the extraction of data and assessment of quality.
The authors declare no conflict of interest and no funding source for the conduct of this research.
Corresponding author:
Geneviève Belleville, PhD École de psychologie
Université Laval, 2325, rue des Bibliothèques Pavillon Félix-Antoine-Savard, local 1116 Québec (QC) G1V 0A6
Genevieve.belleville@psy.ulaval.ca
RÉSUMÉ
Cette méta-analyse sur 33 études vise à déterminer si les personnes avec un TCC risquent davantage de développer un TSPT que celles sans TCC, et si ce risque est plus important dans un contexte militaire que civil. La proportion combinée de TSPT atteint 27% (IC 95% =21,8 à 33,1) dans les groupes TCC, avec un rapport de cote 2,68 fois plus élevé que la proportion de 11% (IC 95% =8,0 à 15,0) obtenue auprès des groupes sans TCC. Les études d’échantillons de militaires et de civils étaient respectivement 4,18 et 1,26 fois plus propices à présenter un TSPT après un TCC qu’en l’absence d’une telle blessure. La propension à développer un TSPT après un TCC était attribuable à la fois aux facteurs méthodologiques des études incluses et aux caractéristiques spécifiques des militaires. La prise en charge du double diagnostic TCC-TSPT devrait être effectuée dans un contexte de collaboration interdisciplinaire.
ABSTRACT
Objectives: To determine whether persons with traumatic brain injury (TBI) are at greater risk of
developing posttraumatic stress disorder (PTSD) than other trauma-exposed populations without TBI, and whether this risk is even greater in military/veteran settings than in civilian settings.
Design: A systematic review and meta-analysis was conducted in 7 databases. Reference lists
from the 33 identified studies and other relevant reviews were also searched. Results: The pooled PTSD proportion reached 27% (95% confidence interval = 21.8-33.1) in groups with TBI, which was 2.68 times greater than the observed 11% (95% confidence interval = 8.0-15.0) in groups without TBI. PTSD after TBI was more frequently observed in military samples than in civilians (37% vs 16%). Military and civilian samples were respectively 4.18 and 1.26 times more inclined to have a diagnosis of PTSD after TBI than when there was no TBI. The proportion of PTSD after TBI was concurrently attributable to the methods of the included studies (objectives focused on PTSD diagnosis, type of comparison group) and to characteristics specific to the military setting (country, sex, blast injuries). Conclusions: TBI diagnosis and military setting represent greater risks for PTSD. The dual diagnosis of TBI and PTSD requires interdisciplinary collaboration, as physical and psychological traumas are closely intertwined.
Key words: comorbidity, diagnosis, meta-analysis, military personnel, posttraumatic
INTRODUCTION
There has been significant debate in the literature regarding whether persons sustaining traumatic brain injury (TBI) could be diagnosed with posttraumatic stress disorder (PTSD) when the injury is severe enough to produce posttraumatic amnesia (PTA) and loss of consciousness. The latter were initially thought to be incompatible with the formation of traumatic memories leading to PTSD,1,2 as it was argued that these patients could not feel nor remember the horror and feeling of helplessness or experience a state of dissociation, because of an altered state of consciousness.1 In recent years, studies and reviews have demonstrated that both civilian and military patients with TBI of various severity levels can develop PTSD.3-13 Several processes have been proposed to explain its development even in severe cases including an increased emotional salience of the event due to structural and functional brain alterations, fear conditioning, resolution of PTA, or memory reconstruction.12,14-17 For example, a patient with severe TBI and no memory of his car accident can experience PTSD symptoms after seeing a journal article of the event.18
Although almost 90% of the populations are exposed to at least one traumatic event in their lifetime, only 8.3% will develop PTSD.19 PTSD is characterized by the development of symptoms following the exposure to one or multiple traumatic events.20,21 Events such as war, terrorism, aggression, disaster or motor vehicle accidents (MVAs) can be both physically and psychologically traumatic, thus putting the individual at risk of comorbid TBI and PTSD. In TBI context, “trauma” or “traumatic” are terms generally used in reference to sudden and severe body injuries,22 and this does not exclude that there may have been psychological trauma. From the PTSD perspective, these terms refer to a psychologically intense experience where there may or may not be any body injury.20
There is evidence for a potentiation effect regarding injury-related symptoms when TBI and PTSD are observed together than when they occur separately.23 Several studies suggest that, compared with other physical injuries, TBI leads to additional risk for diagnosis of PTSD, more severe PTSD symptoms,9,24-31 and extends PTSD remission.28 Other studies
found no difference in the development of PTSD between patients with or without a TBI.32-35 Thus, it remains unclear whether the propensity to develop PTSD is higher in persons with TBI than in other trauma-exposed individuals (i.e. with similar physical and psychological traumas but without TBI).
Military and veterans who served as active duty members possess exclusive characteristics (eg, high level of exposure to combat, higher risk of physical and blast injuries) that increase the risk of developing TBI and/or PTSD. Prevalence for mild TBI (mTBI) in military populations varies from 4.4% to 23% according to different studies, compared with about 12% for TBI of all severity levels in the general population.26,36-40 As for PTSD, lifetime prevalence in the military and veterans populations reaches 14 to 16%,41 compared with 9.8% in the general population.19 Women and men veterans report higher rates of lifetime PTSD (13.4% and 7.7%) compared with their civilian counterparts (8.0% and 3.4%).42 PTSD also seems to be more frequent after blast-induced mTBI than after non- blast-related mTBI,43 but Mac Donald et al.44 did not find any difference between subgroups with blast and nonblast TBI on their propensity to develop PTSD. A systematic review found comorbidity proportions varying from 0% to 70 % across 34 studies, but no difference between military and nonmilitary samples.6 Thus, although higher rates for individual TBI26,36-40 and PTSD19,41-43 suggest a greater comorbidity proportion in military compared to civilian populations, it remains to be verified.
Proportions of TBI-PTSD comorbidity vary largely according to sample characteristics and methodological factors.3,6 For instance, some studies have found higher proportions of PTSD in patients with mTBI than in those with severe TBI; other studies reported that higher TBI severity was associated with increased risk of PTSD.7,27,45,46 Moreover, some mechanisms of injury in TBI are more likely to be psychologically distressing or violent (eg, assault) than others (eg, sport-related) and, thus, more likely to induce PTSD.47,48 Recent conflicts in Afghanistan and Iraq have involved multiple deployments and blast-related injuries are thought to have led to an increased prevalence of TBI and PTSD in the military.49-52 PTSD after TBI is also thought to be higher when assessed with self-report measures than with interviews,3,53 but Carlson and colleagues6
reported no clear difference between the studies in their systematic review. Consequently, no clear conclusions can be drawn for the effect of these variables on the risk of PTSD after TBI.
In the absence of a systematic procedure, quantitative analyses and control of variables that could potentially affect prevalence rates, it remains difficult to draw clear conclusions about the occurrence of TBI-PTSD comorbidity in civilian and military samples. The objectives of this meta-analysis were to determine whether populations with TBI are at greater risk of developing PTSD than other trauma-exposed populations, and whether this risk is even greater in military than in civilian settings. A secondary aim was to observe the impact of potential moderators (ie, type of diagnostic tool used to assess PTSD and TBI, type of comparison group, study quality, design, scope of objectives, sample size, time since injury, type of psychological trauma, TBI severity, country of research setting, sex and mean age) on PTSD following TBI.