Is inflammatory change associated with psychological risk and resilience in high-risk military personnel?

INTRODUCTION: In military populations, the potential for under-reporting of Post-traumatic Stress Disorder (PTSD) symptoms and challenges in recognising early changes can make it difficult to detect an emerging disorder. However, early identification of PTSD symptoms would improve opportunities for intervention, and potentially reduce the likelihood of chronic mental health problems. METHOD: This study explored if changes in levels of inflammation, measured by C reactive protein (CRP) and interleukin 6 (IL-6), were associated with the onset of psychological symptoms associated with PTSD. It also examined if changes in inflammation over time contributed to psychological risk and resilience, which was defined by psychological reactivity to deployment-related combat exposures. Participants were special forces personnel who completed psychological self-report questionnaires and had measures of CRP and IL-6 taken pre and post deployment. Regression analysis was used to examine how psychological symptoms predicted change in inflammation, and Analysis of Variance (ANOVA) were used to examine differences between identified subgroups. RESULTS: Results identify this population as having high levels of combat and trauma exposures, with low-level psychological symptoms. The results also identified a decrease in CRP and an increase in IL-6 over time. A significant difference in inflammation was identified between subgroups (p<0.05). An association between inflammatory markers and subthreshold symptoms related to anger (p<0.01) and sleep (p<0.05) was also identified. CONCLUSION: These preliminary findings suggest inflammatory markers may help to identify adaptive responses post deployment. In addition, low-level increases in inflammatory markers may be associated with subthreshold PTSD symptoms. These findings offer potential insights for prevention, early identification and treatment in military and veteran populations.

Identifying psychological risk and resilience in high-risk military personnel.

INTRODUCTION: Combat exposure has been associated with the emergence of post-traumatic stress disorder (PTSD) symptoms in military personnel; however, not all veterans are negatively impacted by their operational experience. In many instances, the absence of symptoms following operational service is attributed to resilience. This study explored the construct of resilience by examining the relationship between levels of deployment-related exposures and psychological symptoms, as well as identifying factors that may contribute to resilience and emerging risk. METHOD: Participants were special forces personnel who completed self-report questionnaires 1 month before deployment and 4 months post deployment. Subgroups were created based on psychological reactivity to deployment exposures, representing risk, vulnerability and resilience. Regression analysis assessed the contribution of factors that were predictive of risk or resilience groups specifically. RESULTS: Results showed the overall levels of psychological reactivity in this population post deployment were low; however, differences between risk and resilience subgroups were found. Subthreshold indicators of psychological reactivity, as well as deployment factors such as increased deployment frequency and time spent away from home, were found to contribute to differences between risk and resilient trajectories. CONCLUSION: Findings reflect a military population with low psychological symptoms despite high trauma exposure. However, subtle underlying differences between subgroups suggest that the early identification of risk and emerging trajectories is possible. Risk and resilience in military populations needs to consider subthreshold indicators and individual differences over time.

Prevalence and implications of gambling problems among firefighters.

Firefighting is a high-risk occupation that accounts for vulnerability to a range of mental health problems and addictive behaviours. However, no research has addressed whether this vulnerability extends to gambling problems, and the aim of this study was thus to provide new data on frequency and implications of such problems in this occupational context. The sample consisted of n = 566 career and retained firefighters who participated in a cross-sectional survey of an Australian metropolitan fire service. The Problem Gambling Severity Index (PGSI) was used to operationalise both clinically significant levels of problem gambling (PGSI ≥ 5), and 'at-risk' gambling (PGSI 1-4); alongside measures of major depression (PHQ-9), anxiety (GAD-7), Posttraumatic Stress Disorder (PCL-5) and alcohol problems (AUDIT), as well as other addictive behaviours, wellbeing and psychosocial issues. Results indicated 12.3% of firefighters that reported any gambling problems across a continuum of severity (PGSI ≥ 1), including 2.3% that were problems gamblers, and 10.0% reporting at-risk gambling. The weighted prevalence of problem gambling was comparable to other significant mental health conditions including depression and PTSD, while the rate of any gambling problems was high relative to other addictive behaviours. Gambling problems were associated with poor mental health and wellbeing, but not psychosocial indicators (e.g., financial difficulties). The findings suggest that gambling problems across a spectrum of severity may be significant yet hidden issues among emergency service workers, and thus require increased recognition and responses at the organisational level.

A population study of prolonged grief in refugees.

AIMS: Despite the frequency that refugees suffer bereavement, there is a dearth of research into the prevalence and predictors of problematic grief reactions in refugees. To address this gap, this study reports a nationally representative population-based study of refugees to determine the prevalence of probable prolonged grief disorder (PGD) and its associated problems. METHODS: This study recruited participants from the Building a New Life in Australia (BNLA) prospective cohort study of refugees admitted to Australia between October 2013 and February 2014. The current data were collected in 2015-2016, and comprised 1767 adults, as well as 411 children of the adult respondents. Adult refugees were assessed for trauma history, post-migration difficulties, probable PGD, post-traumatic stress disorder (PTSD) and mental illness. Children were administered the Strengths and Difficulties Questionnaire. RESULTS: In this cohort, 38.1% of refugees reported bereavement, of whom 15.8% reported probable PGD; this represents 6.0% of the entire cohort. Probable PGD was associated with a greater likelihood of mental illness, probable PTSD, severe mental illness, currently unemployed and reported disability. Children of refugees with probable PGD reported more psychological difficulties than those whose parents did not have probable PGD. Probable PGD was also associated with the history of imprisonment, torture and separation from family. Only 56.3% of refugees with probable PGD had received psychological assistance. CONCLUSIONS: Bereavement and probable PGD appear highly prevalent in refugees, and PGD seems to be associated with disability in the refugees and psychological problems in their children. The low rate of access to mental health assistance for these refugees highlights that there is a need to address this issue in refugee populations.

Respiratory syncytial virus infection influences tight junction integrity.

Respiratory syncytial virus (RSV) is an important risk factor of asthma development and is responsible for severe respiratory tract infections. However, the influence of RSV infection on barrier function of bronchial epithelial cells in vitro and in vivo is still unclear. The aim of this study was to analyse the role of RSV in tight junction (TJ) regulation and to compare epithelial integrity between asthmatic and healthy individuals upon RSV infection. Healthy and asthmatic human bronchial epithelial cells (HBECs) were differentiated at air-liquid interface (ALI) and infected with RSV and ultraviolet (UV)-irradiated RSV. TJ expression and their integrity were analysed by quantitative polymerase chain reaction (qPCR), transepithelial resistance (TER) and paracellular flux. To determine the effect in vivo, BALB/c mice were infected intranasally with RSV or UV-irradiated RSV A2. Bronchoalveolar lavage and TJ integrity were analysed on days 1, 2, 4 and 6 post-infection by qPCR, bioplex and confocal microscopy. RSV increased barrier integrity in ALI cultures of HBEC from healthy subjects, but no effect was found in HBECs from asthmatics. This was not associated with an increase in TJ mRNA expression. In vivo, RSV induced lung inflammation in mice and down-regulated claudin-1 and occludin mRNA expression in whole lungs. Surprisingly, RSV infection was not observed in bronchial epithelial cells, but was found in the lung parenchyma. Decreased expression of occludin upon RSV infection was visible in mouse bronchial epithelial cells in confocal microscopy. However, there was no regulation of claudin-1 and claudin-7 at protein level.

Separation from parents during childhood trauma predicts adult attachment security and post-traumatic stress disorder.

BACKGROUND: Prolonged separation from parental support is a risk factor for psychopathology. This study assessed the impact of brief separation from parents during childhood trauma on adult attachment tendencies and post-traumatic stress. METHOD: Children (n = 806) exposed to a major Australian bushfire disaster in 1983 and matched controls (n = 725) were assessed in the aftermath of the fires (mean age 7-8 years) via parent reports of trauma exposure and separation from parents during the fires. Participants (n = 500) were subsequently assessed 28 years after initial assessment on the Experiences in Close Relationships scale to assess attachment security, and post-traumatic stress disorder (PTSD) was assessed using the PTSD checklist. RESULTS: Being separated from parents was significantly related to having an avoidant attachment style as an adult (B = -3.69, s.e. = 1.48, ß = -0.23, p = 0.013). Avoidant attachment was associated with re-experiencing (B = 0.03, s.e. = 0.01, ß = 0.31, p = 0.045), avoidance (B = 0.03, s.e. = 0.01, ß = 0.30, p = 0.001) and numbing (B = 0.03, s.e. = 0.01, ß = 0.30, p < 0.001) symptoms. Anxious attachment was associated with re-experiencing (B = 0.03, s.e. = 0.01, ß = 0.18, p = 0.001), numbing (B = 0.03, ß = 0.30, s.e. = 0.01, p < 0.001) and arousal (B = 0.04, s.e. = 0.01, ß = 0.43, p < 0.001) symptoms. CONCLUSIONS: These findings demonstrate that brief separation from attachments during childhood trauma can have long-lasting effects on one's attachment security, and that this can be associated with adult post-traumatic psychopathology.

The longitudinal relationship between post-traumatic stress disorder and perceived social support in survivors of traumatic injury.

BACKGROUND: Although perceived social support is thought to be a strong predictor of psychological outcomes following trauma exposure, the temporal relationship between perceived positive and negative social support and post-traumatic stress disorder (PTSD) symptoms has not been empirically established. This study investigated the temporal sequencing of perceived positive social support, perceived negative social support, and PTSD symptoms in the 6 years following trauma exposure among survivors of traumatic injury. METHOD: Participants were 1132 trauma survivors initially assessed upon admission to one of four Level 1 trauma hospitals in Australia after experiencing a traumatic injury. Participants were followed up at 3 months, 12 months, 24 months, and 6 years after the traumatic event. RESULTS: Latent difference score analyses revealed that greater severity of PTSD symptoms predicted subsequent increases in perceived negative social support at each time-point. Greater severity of PTSD symptoms predicted subsequent decreases in perceived positive social support between 3 and 12 months. High levels of perceived positive or negative social support did not predict subsequent changes in PTSD symptoms at any time-point. CONCLUSIONS: Results highlight the impact of PTSD symptoms on subsequent perceived social support, regardless of the type of support provided. The finding that perceived social support does not influence subsequent PTSD symptoms is novel, and indicates that the relationship between PTSD and perceived social support may be unidirectional.

Stability of symptom patterns in Australian Gulf War veterans: 10-year longitudinal study.

OBJECTIVES: Previously we established that symptoms reported by 1990-1991 Gulf War veterans were correlated and exhibited a pattern with 3 factors (psychophysiological distress, somatic distress and arthroneuromuscular distress), and this pattern was similar to that observed in a military comparison group. In this follow-up study, we examined whether the patterns of symptomatology have changed over time. METHODS: Using data on 56 symptoms that was collected in 2000-2003 (wave 1) and 2011-2012 (wave 2) from an Australian cohort of Gulf War veterans (veterans) and a military comparison group, exploratory factor analysis was conducted and Tucker's Congruence Coefficient (TCC) was used to determine factor structure similarity across study groups and waves. RESULTS: The results showed that the 3 factors observed at wave 1 were still present at wave 2, and factor structures across study groups and study waves were fairly similar, with TCC ranging 0.86-0.92. Veterans consistently reported more symptoms across all 3 factors. Veterans' symptomatology specific to psychophysiological distress increased between waves 1 and 2 (ratio of means 1.15; 95% CI 1.07 to 1.25) but psychophysiological distress symptomatology was constant in the comparison group (ratio of means 0.97; 95% CI 0.89 to 1.06). Somatic and arthroneuromuscular distress symptomatology significantly increased over time for both study groups, although at a similar rate. CONCLUSIONS: While the symptom groupings (measured by the 3 factors) remained unchanged at 10 years of follow-up, and remained comparable between Gulf War and comparison group, symptomatology continued to be elevated in Gulf War veterans than in the comparison group, and was most evident for psychophysiological distress.

Major depression and depressive symptoms in Australian Gulf War veterans 20 years after the Gulf War.

BACKGROUND: Risk of major depression (depression) was elevated in Australia's Gulf War veterans in a 2000-2002 (baseline) study. A follow up study has measured the Gulf War-related risk factors for depression, also the current prevalence and severity of depression, use of anti-depressant medication, and persistence, remittance or incidence of depression since baseline in Gulf War veterans and a military comparison group. METHODS: Participants completed the Composite International Diagnostic Interview v.2.1, the 9-item Patient Health Questionnaire and the Military Service Experience Questionnaire, and consented to Repatriation Pharmaceutical Benefits Scheme (RPBS) and PBS linkage. RESULTS: Prevalence of depression (9.7% Gulf War veterans and 7.7% comparison group; adj RR=1.2, 95% CI 0.8-1.7), and pattern of persistence, remittance and incidence of depression since baseline, were similar in the two groups, however veterans reported slightly more severe symptoms (adj median difference 1, 95% CI 0.26-1.74) and were more likely to have been dispensed anti-depressant medication (adj RR=1.56, 95% CI 1.05-2.32). Depression amongst veterans was associated with self-reported Gulf War-related stressors in a dose-response relationship (adj RR 1.06, 95% CI 1.02-1.09). LIMITATIONS: Lower participation rates at follow up resulted in reduced statistical power compared with baseline, Gulf War related stressor data collected at baseline was at risk of recall bias, and RPBS and PBS databases do not capture all dispensed Nervous System medications. CONCLUSIONS: More than 20 years after the Gulf War, veterans are experiencing slightly more severe depressive symptoms than a military comparison group, and depression continues to be associated with Gulf War-related stressors.

ICSH recommendations for assessing automated high-performance liquid chromatography and capillary electrophoresis equipment for the quantitation of HbA2.

Automated high performance liquid chromatography and Capillary electrophoresis are used to quantitate the proportion of Hemoglobin A2 (HbA2 ) in blood samples order to enable screening and diagnosis of carriers of ß-thalassemia. Since there is only a very small difference in HbA2 levels between people who are carriers and people who are not carriers such analyses need to be both precise and accurate. This paper examines the different parameters of such equipment and discusses how they should be assessed.

Internal Quality Control Practices in Coagulation Laboratories: recommendations based on a patterns-of-practice survey.

INTRODUCTION: Internal quality control (IQC) procedures are crucial for ensuring accurate patient test results. The IQMH Centre for Proficiency Testing conducted a web-based survey to gather information on the current IQC practices in coagulation testing. METHODS: A questionnaire was distributed to 174 Ontario laboratories licensed to perform prothrombin time (PT) and activated partial thromboplastin time (APTT). RESULTS: All laboratories reported using two levels of commercial QC (CQC); 12% incorporate pooled patient plasma into their IQC program; >68% run CQC at the beginning of each shift; 56% following maintenance, with reagent changes, during a shift, or with every repeat sample; 6% only run CQC at the beginning of the day and 25% when the instruments have been idle for a defined period of time. IQC run frequency was determined by manufacturer recommendations (71%) but also influenced by the stability of test (27%), clinical impact of an incorrect test result (25%), and sample's batch number (10%). IQC was monitored using preset limits based on standard deviation (66%), precision goals (46%), or allowable performance limits (36%). 95% use multirules. Failure actions include repeating the IQC (90%) and reporting patient results; if repeat passes, 42% perform repeat analysis of all patient samples from last acceptable IQC. CONCLUSION: Variability exists in coagulation IQC practices among Ontario clinical laboratories. The recommendations presented here would be useful in encouraging standardized IQC practices.

Hemoglobin H identification by high-performance liquid chromatography in confirmed hemoglobin H disease.

INTRODUCTION: Among hemoglobin (Hb) H disease cases diagnosed by DNA testing in our hemoglobinopathy laboratory, we have noted instances of unreported Hb H from high-performance liquid chromatography (HPLC) results of referring laboratories. METHODS: To characterize these issues, we identified all cases of genotypic Hb H disease diagnosed in our laboratory. HPLC chromatograms were reviewed to determine the presence and retention time of the Hb H peak. RESULTS: Hemoglobin H was not reported in 24.2% of patients (23 of 95) with genotypic Hb H disease. The characteristic prerun peak of Hb H was present on review of all eight Variant or Variant II ß-thalassemia short-program chromatograms. Elevated Hb F (≥3%) was reported in 14 cases. The Hb H peak was found in the Hb F window in 11 dual program cases. The incorrect identification of Hb H as elevated Hb F resulted in two testing referrals for 'δß-thalassemia'. CONCLUSIONS: Hemoglobin H may go unreported due to failure to examine for or recognize its peak on Variant or Variant II ß-thalassemia short-program chromatograms. Elution of Hb H in the Hb F window resulted in misidentification of Hb H for Hb F and may indicate a Variant II HbA2 /HbA1C program software error. Our findings highlight the need for careful chromatogram inspection and clinical correlation in the diagnosis of Hb H disease.

Effect of biologics on depressive symptoms in patients with psoriasis: a systematic review.

BACKGROUND: Twenty to fifty percent of patients with psoriasis have depressive symptoms. OBJECTIVE: To describe the effects of biologics (tumour necrosis factor inhibitors [TNFi] or interleukin 12/23 inhibitors [IL-12/23i]) on depressive symptoms in patients with psoriasis. METHODS: Electronic databases were searched for randomized controlled trials (RCTs) examining the effects of biologics on depressive symptoms in adults with psoriasis. RESULTS: Of the 305 publications identified, three RCTs were included in a systematic review. In a trial evaluating ustekinumab, mean change in Hospital and Anxiety Depression Rating Scale at 24 weeks from baseline was 3.1 with ustekinumab (P < 0.001) vs. 0.21 with placebo (not significant). In a trial evaluating adalimumab, mean change in Zung Self-Rating Depression Scale at 12 weeks from baseline was -6.7 with adalimumab vs. -1.5 with placebo. In a trial evaluating etanercept, the between-group difference at 12 weeks in Beck Depression Inventory Scale was 1.8 (95% CI: 0.6, 2.90) in favour of etanercept over placebo. Limitations are that diagnostic criteria for depression were not used and scales and data from individual RCTs could not be combined. CONCLUSION: Adalimumab, etanercept and ustekinumab were associated with statistically significant reductions in depressive symptom scores using various scales in patients with moderate-to-severe psoriasis.

Critical values in hematology.

INTRODUCTION: Critical values are life-threatening results that require immediate notification to the patient's healthcare provider. Accreditation bodies require laboratories to establish critical values. A survey of Ontario laboratories was conducted to determine current practice for critical values in hematology. METHODS: The survey was sent to 182 participants questioning sources for establishing critical values, levels, review frequency, delta checks, and reporting. The survey was completed by laboratory managers, supervisors, technical specialists, senior technologists, and bench technologists working in hematology. RESULTS: The majority of participating laboratories have established critical values limits for hemoglobin, leukocyte counts, and platelet counts. Most laboratories also include the presence of malaria parasites and blast cells. Some laboratories reported the presence of plasma cells, sickle cells, schistocytes, and spherocytes as critical values. Multiple sources are used for establishing a critical value policy. There was variability for the frequency of critical values review. Rules may differ for a first-time patient sample vs. a repeat patient sample. Delta checks are seldom used to determine whether a result should be called a critical value. Most participants require the individual taking the critical result(s) to read back and confirm that they are directly involved with the patient's care. CONCLUSION: There is a lack of consensus for critical values reporting in hematology. As critical value reporting is crucial for patient safety, standardization of this practice would be beneficial.

Too much work, not enough tarsi: group size influences Bombus impatiens (Hymenoptera: Apidae) worker reproduction with implications for sublethal pesticide toxicity assessments.

As bumble bees may routinely forage on pesticide-treated plants, it is imperative to apply pesticides that pose minimal risk. Identifying such reduced-risk pesticides requires toxicity tests using biologically relevant and standardized exposure methods. Our goal was to develop a functional and reliable queen-less micro-colony method for determining the sublethal effects of pesticides on Bombus impatiens Cresson, a species for which further toxicity assessments are needed. Originally developed using Bombus terrestris (L.), this method involves isolating three workers and allowing them to establish and maintain a colony. The workers and brood can then be exposed to pesticides and various effects measured simultaneously. Our preliminary work indicated that B. impatiens workers were unable to reproduce under the micro-colony conditions developed for B. terrestris. In the current study, we focused on the potential role of group size in B. impatiens worker reproduction by placing groups of three or five sister workers together and assessing their ability to establish a colony and rear males to adulthood. While both groups oviposited and produced males, significantly more males emerged from micro-colonies of five workers. We conclude that group size affects B. impatiens worker reproduction, and this effect in bumble bees varies interspecifically. In the context of toxicity testing, we recommend the use of at least five B. impatiens workers in micro-colonies to ensure a level of reproduction that allows the detection of potential sublethal changes to reproduction or development.

Mental health services required after disasters: learning from the lasting effects of disasters.

Disasters test civil administrations' and health services' capacity to act in a flexible but well-coordinated manner because each disaster is unique and poses unusual challenges. The health services required differ markedly according to the nature of the disaster and the geographical spread of those affected. Epidemiology has shown that services need to be equipped to deal with major depressive disorder and grief, not just posttraumatic stress disorder, and not only for victims of the disaster itself but also the emergency service workers. The challenge is for specialist advisers to respect and understand the existing health care and support networks of those affected while also recognizing their limitations. In the initial aftermath of these events, a great deal of effort goes into the development of early support systems but the longer term needs of these populations are often underestimated. These services need to be structured, taking into account the pre-existing psychiatric morbidity within the community. Disasters are an opportunity for improving services for patients with posttraumatic psychopathology in general but can later be utilized for improving services for victims of more common traumas in modern society, such as accidents and interpersonal violence.

Remission from post-traumatic stress disorder in the general population.

BACKGROUND: Few studies have focused on post-traumatic stress disorder (PTSD) remission in the population, none have modelled remission beyond age 54 years and none have explored in detail the correlates of remission from PTSD. This study examined trauma experience, symptom severity, co-morbidity, service use and time to PTSD remission in a large population sample. METHOD: Data came from respondents (n=8841) of the 2007 Australian National Survey of Mental Health and Wellbeing (NSMHWB). A modified version of the World Health Organization's World Mental Health Composite International Diagnostic Interview (WMH-CIDI) was used to determine the presence and age of onset of DSM-IV PTSD and other mental and substance use disorders, type, age, and number of lifetime traumas, severity of re-experiencing, avoidance and hypervigilance symptoms and presence and timing of service use. RESULTS: Projected lifetime remission rate was 92% and median time to remission was 14 years. Those who experienced childhood trauma, interpersonal violence, severe symptoms or a secondary anxiety or affective disorder were less likely to remit from PTSD and reported longer median times to remission compared to those with other trauma experiences, less severe symptoms or no co-morbidity. CONCLUSIONS: Although most people in the population with PTSD eventually remit, a significant minority report symptoms decades after onset. Those who experience childhood trauma or interpersonal violence should be a high priority for intervention.

Heart rate after trauma and the specificity of fear circuitry disorders.

BACKGROUND: Fear circuitry disorders purportedly include post-traumatic stress disorder (PTSD), panic disorder, agoraphobia, social phobia and specific phobia. It is proposed that these disorders represent a cluster of anxiety disorders triggered by stressful events and lead to fear conditioning. Elevated heart rate (HR) at the time of an aversive event may reflect strength of the unconditioned response, which may contribute to fear circuitry disorders. METHOD: This prospective cohort study assessed HR within 48 h of hospital admission in 602 traumatically injured patients, who were assessed during hospital admission and within 1 month of trauma exposure for lifetime psychiatric diagnosis. At 3 months after the initial assessment, 526 patients (87%) were reassessed for PTSD, major depressive disorder, panic disorder, agoraphobia, social phobia, obsessive compulsive disorder and generalized anxiety disorder. RESULTS: At the 3-month assessment there were 77 (15%) new cases of fear circuitry disorder and 87 new cases of non-fear circuitry disorder (17%). After controlling for gender, age, type of injury and injury severity, patients with elevated HR (defined as ≥96 beats per min) at the time of injury were more likely to develop PTSD [odds ratio (OR) 5.78, 95% confidence interval (CI) 2.32-14.43], panic disorder (OR 3.46, 95% CI 1.16-10.34), agoraphobia (OR 3.90, 95% CI 1.76-8.61) and social phobia (OR 3.98, 95% CI 1.42-11.14). Elevated HR also predicted new fear circuitry disorders that were not co-morbid with a non-fear circuitry disorder (OR 7.28, 95% CI 2.14-24.79). CONCLUSIONS: These data provide tentative evidence of a common mechanism underpinning the onset of fear circuitry disorders.

Support for the mutual maintenance of pain and post-traumatic stress disorder symptoms.

BACKGROUND: Pain and post-traumatic stress disorder (PTSD) are frequently co-morbid in the aftermath of a traumatic event. Although several models attempt to explain the relationship between these two disorders, the mechanisms underlying the relationship remain unclear. The aim of this study was to investigate the relationship between each PTSD symptom cluster and pain over the course of post-traumatic adjustment. METHOD: In a longitudinal study, injury patients (n=824) were assessed within 1 week post-injury, and then at 3 and 12 months. Pain was measured using a 100-mm Visual Analogue Scale (VAS). PTSD symptoms were assessed using the Clinician-Administered PTSD Scale (CAPS). Structural equation modelling (SEM) was used to identify causal relationships between pain and PTSD. RESULTS: In a saturated model we found that the relationship between acute pain and 12-month pain was mediated by arousal symptoms at 3 months. We also found that the relationship between baseline arousal and re-experiencing symptoms, and later 12-month arousal and re-experiencing symptoms, was mediated by 3-month pain levels. The final model showed a good fit [chi2=16.97, df=12, p>0.05, Comparative Fit Index (CFI)=0.999, root mean square error of approximation (RMSEA)=0.022]. CONCLUSIONS: These findings provide evidence of mutual maintenance between pain and PTSD.