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1 ORIGINAL ARTICLE AQ:1 Early Stage Assessment and Course of Acute Stress Disorder After Mild Traumatic Brain Injury Luke GJ. Broomhall, MPsych,* Richard C. Clark, PhD,* Alexander C. McFarlane, MBBS(Hons), MD, Meagan O Donnell, PhD, Richard Bryant, PhD, Mark Creamer, PhD, and Derek Silove, PhD AQ:2 AQ:9 AQ:10 Abstract: Although it has been established that acute stress disorder (ASD) and posttraumatic stress disorder occur after mild traumatic brain injury (MTBI) the qualitative differences in symptom presentation between injury survivors with and without a MTBI have not been explored in depth. This study aimed to compare the ASD and posttraumatic stress disorder symptom presentation of injury survivors with and without MTBI. One thousand one hundred sixteen participants between the ages of 17 to 65 years (mean age: years, SD: 14.23) were assessed in the acute hospital after a traumatic injury. Four hundred seventy-five individuals met the criteria for MTBI. Results showed a trend toward higher levels of ASD in the MTBI group compared with the non-mtbi group. Those with a MTBI and ASD had longer hospital admissions and higher levels of distress associated with their symptoms. Although many of the ASD symptoms that the MTBI group scored significantly higher were also part of a postconcussive syndrome, higher levels of avoidance symptoms may suggest that this group is at risk for longer term poor psychological adjustment. Mild TBI patients may represent a injury group at risk for poor psychological adjustment after traumatic injury. Key Words: Acute stress disorder, mild traumatic brain injury, posttraumatic stress disorder. (J Nerv Ment Dis 2009;197: ) Traumatic Brain Injury (TBI) occurs at a rate of 30,000 per year in Australia, mostly from motor vehicle accidents (MVAs). Approximately 15,000 TBI survivors experience a mild traumatic brain injury (MTBI) (Rees, 2005). Although the majority of these injury survivors will recover without residual impairment, problems persist in 15% to 25% of cases (Gronwall and Wrightson, 1981; Ponsford et al., 2000). Exploring the factors that underpin this impairment represents an important direction of enquiry. Acute stress disorder (ASD) is a psychiatric disorder that may occur after traumatic events. Entry criteria for an ASD diagnosis requires an individual to be exposed to a traumatic event which involved: (1) actual (or threatened) injury to physical integrity of self or others; and (2) an emotional response of intense fear, helplessness or horror. ASD places a large emphasis on dissociation, requiring a minimum of 3 of 5 dissociative experiences either during or after the traumatic event. These dissociative experiences include *School of Psychology, Flinders University, Adelaide, South Australia, Australia; School of Psychiatry, University of Adelaide, Adelaide, South Australia, Australia; Department of Psychiatry, University of Melbourne, Victoria, Australia; and School of Psychology, University of New South Wales, New South Wales, Australia. Supported by a National Health and Medical Research Council Program Grant (300304), a Victorian Trauma Foundation grant (V-11), and a National Health and Medical Research Council Australian Clinical Research Fellowship (359284). Send reprint requests to Luke G.J. Broomhall, MPsych, School of Psychology, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia. luke.broomhall@flinders.edu.au. Copyright 2009 by Lippincott Williams & Wilkins ISSN: /09/ DOI: /NMD.0b013e318199fe7f a subjective sense of emotional numbing, reduced awareness, derealisation, depersonalisation, and dissociative amnesia. ASD requires at least 1 symptom in the re-experiencing, arousal, and avoidance clusters. A diagnosis of ASD requires clinically significant distress or impairment in social, occupational or other important areas of functioning. There has been significant debate over the years as to whether an individual who sustains a MTBI could experience posttraumatic stress symptoms. The argument that TBI may protect against the development of trauma-related psychopathology arises from the view that brain injury reduces the likelihood that trauma information is encoded and thus is not recalled (Sbordone and Liter, 1995). Without the painful, traumatic memories, individuals cannot develop the typical constellation of posttraumatic stress disorder (PTSD) symptoms characterized by intrusive re-experiencing of the traumatic event. This view is supported by research that found that individuals with brain injury are less likely to develop PTSD (Mayou et al., 1993; Sbordone and Liter, 1995). These studies, however, have been criticized on methodological grounds suggesting cautious interpretation of these results (Bryant, 2001; McMillan, 1997). Furthermore, there is now strong evidence that PTSD and ASD do develop after MTBI (Bryant, 2001; Bryant and Harvey, 1999; Carty et al., 2006; Creamer et al., 2005; Harvey and Bryant, 1998; Harvey and Bryant 2000; Ohry et al., 1996). A new line of research enquiry is now directed to whether there are qualitative differences in the development of acute stress symptoms between those with and without MTBI. Research investigating the acute stress symptom differences between injury survivors with and without MTBI is relatively sparse. Harvey and Bryant (1998) were among the first to investigate rates of ASD in a population of MTBI patients and found that 13% of participants who sustained a MTBI developed ASD within 1 month of injury. This was seen as comparable with rates seen generally in the non-mtbi injury population. Of those in the MTBI group with ASD (13%), 82% met the diagnostic criteria for PTSD at 6-month follow-up. At 2-year follow-up, 22% of the original sample who could be assessed met the criteria for PTSD and 80% of those with ASD met the criteria for PTSD (Harvey and Bryant, 2000). The strong predictive power of ASD symptoms such as numbing and depersonalisation was viewed as supporting the view that dissociative mechanisms may prevent the processing and integration of trauma related information at the time of the event. Although ASD is useful in identifying who will go on to develop later PTSD, it is well recognized that not everyone who develops PTSD will have an earlier ASD diagnosis (Bryant, 2005). One of the difficulties in assessing ASD within TBI populations is the overlap between the ASD symptoms and the MTBI postconcussive syndrome (PCS). PCS includes symptoms of headaches, dizziness, fatigue, irritability, reduced concentration, sleep disturbance, anxiety, sensitivity to noise and light, double or blurred vision, and depression (Frencham et al., 2005). It is clear that there is an overlap between symptoms of ASD and PCS including irritability, reduced concentration and sleep disturbance. Furthermore, the ASD dissociative symptoms of psychogenic amnesia, reduction in AQ:3 The Journal of Nervous and Mental Disease Volume 197, Number 3, March

2 Broomhall et al. The Journal of Nervous and Mental Disease Volume 197, Number 3, March 2009 AQ:4 AQ:5 awareness of surroundings, and derealisation are similar to experiences that occur in a PCS. In recognition of this potential overlap, most studies that assess ASD or PTSD using MTBI samples exclude psychogenic amnesia from the diagnosis (Bryant and Harvey, 1998; O Donnell et al., 2004; Schnyder et al., 2001). No study to date has thoroughly investigated symptom overlap between MTBI and ASD. Furthermore, the majority of studies examining ASD in MTBI populations have had relatively small sample sizes. The aim of this study was to replicate and extend previous studies by conducting a large, mulitsited, prospective study that (1) compared the rates of ASD between injury survivors with and without a MTBI; (2) identified whether MTBI participants with ASD differ from those without ASD on characteristics such as Injury Severity Score (ISS) and length of stay; and (3) compared the ASD symptom profile between injury survivors with and without a MTBI. METHOD Participants Participants were randomized admissions to 4 level 1 trauma hospitals across 3 Australian states: New South Wales, South Australia, and Victoria. The study was approved by the Research and Ethics Committee at each hospital. Participants were included in the study if they had a physical injury that required an admission of at least 24 hours to the trauma service. Participants were excluded from the study if they were aged greater than 65 years, less than 16 years of age, had a moderate or severe brain injury, if they were currently suicidal or psychotic, or were a non-english speaker. Participants were provided with written information regarding the research and provided written informed consent to participate before commencement of the study. An individual s MTBI status was determined from information obtained from ambulance, hospital records, and ongoing assessment. An individual was identified as having a MTBI if they met the definition proposed by the American Congress of Rehabilitation Medicine (American Congress of Rehabilitation Medicine, 1993) that defines MTBI as requiring at least one of the following: a loss of consciousness of approximately 30 minutes or less, a Glasgow Coma Scale score of 13 to 15 after 30 minutes, or posttraumatic amnesia (PTA) not greater that 24 hours. One thousand six hundred fifteen patients were randomized into the study. Of these 424 patients refused (26%), 36 (2%) patients were not assessed due to unexpected discharge, and 39 (2%) patients withdrew. Individuals who refused to participate in the current study did not differ from participators in gender (chi square 0.8; df 1; ns), length of hospital admission (t 1, , ns), ISS (t 1, , ns), or age (t 1, , ns). A total of 1116 participants completed the Clinician Administered PTSD Scale (CAPS). There were 828 men (71.9%) and 300 (26.1%) women with a mean age of 38 years (SD: 14.23). Participants spent an average of days in hospital (SD: 11.68) and the mean ISS (Baker et al., 1974) was (SD: 7.95). Participants were assessed on average 6.73 days after trauma (SD: 6.94). Average length of hospital stay was days (SD: 11.67) with a range of 2 to 88 days. Mechanism of injury in the overall sample consisted of 718 (64.3%) motor vehicle accidents, 164 (14.7%) falls, 68 (6.1%) assaults, 76 (6.8%) work related accidents and 83 (7.4%) other injuries. Four hundred seventy-six (42.7%) individuals (347 men and 129 women) met the criteria for MTBI. Materials and Procedure Acute Stress Disorder The CAPS (Blake et al., 1998) with its dissociation questions was used as a measure of ASD. This structured clinical interview is 2 one of the most widely used tools for diagnosing PTSD and measuring PTSD severity, has demonstrated excellent reliability and validity (Weathers et al., 2001), and has been used to assess ASD in past research (O Donnell et al., 2004). The presence of a diagnosis of ASD in the current research was evaluated after excluding dissociative amnesia to avoid potential overlap between dissociative and organic amnesia after MTBI. ASD was scored using DSM-IV criteria the presence of at least 1 re-experiencing symptom, 1 avoidance symptom, 1 arousal symptom, and at least 3 dissociative symptoms. Subsyndromal ASD was diagnosed as the presence of at least 1 symptom in each cluster of symptoms. Following common practice, both ASD and PTSD were scored using the 1 to 2 rule (i.e., diagnostic criteria were met for each symptom if frequency 1 and intensity 2) (Weathers et al., 1999). Five percent of all CAPS interviews were rescored blind to the original scoring to test inter-rater reliability. Overall, the PTSD diagnostic consistency for the CAPS was 1.00 at 3 months and 0.98 at 12 months. Study interviewers were trained in the study protocol (including the administration of the CAPS) by a clinical psychologist and all assessments were recorded to ensure ongoing adherence to the protocol. Data Analyses Descriptive analyses were used to quantify the diagnosis of ASD and the frequency of each ASD symptom. T-tests and chi square analyses were used to determine differences between ASD and non-asd groups in the MTBI and non-mtbi populations on a range of patient characteristics (length of hospital stay, previous psychiatric diagnoses, and ISS). Chi square analyses were conducted on each individual ASD symptom to determine differences between ASD and non-asd group in the MTBI population and in the non-mtbi population. To test for a difference between the MTBI and non-mtbi groups in the prevalence of the reporting of each ASD symptom, a log binomial regression model was fitted to the data. p values for comparisons of individual ASD symptoms between the general trauma patients and MTBI patients were adjusted for multiple comparisons using the stepdown Sidak method. RESULTS Acute Stress Disorder ASD was diagnosed in 3.42% (n 37) of the overall sample. In the MTBI group, 4.62% individuals (n 22) met the diagnostic criteria for ASD, whereas 2.47% individuals (n 15) of the non-mtbi group were diagnosed with ASD. The difference between these groups in terms of comparative rates of ASD approached significance (chi square ; p 0.057). Participants with MTBI reported a significantly higher incidence subsyndromal ASD (chi square , p 0.01) with 19.12% of those in the MTBI group (n 91) relative to 12.85% in the non-mtbi group (n 78) meeting diagnostic criteria. Table 1 shows a comparison between ASD and non-asd groups for both MTBI and non-mtbi groups on patient characteristics. The MTBI group with ASD spent significantly longer in hospital than both the MTBI without ASD (t 1, ; p 0.05) and the non-mtbi without ASD (t 1, ; p 0.01). There were no significant differences in length of hospital stays between the remaining groups. There was no significant difference in ISS, between those with and without a MTBI. Those participants, however, in the MTBI with ASD group had a significantly higher ISS than both the non-mtbi with ASD group (t 1, , p 0.01) and the non-mtbi without ASD group (t 1, ; p 0.01). Similarly, the MTBI group without ASD had significantly higher ISS than both non-mtbi with ASD (t 1, ; p 0.01) and the non-mtbi without ASD (t 1, ; p 0.001) Lippincott Williams & Wilkins AQ:6 T1

3 The Journal of Nervous and Mental Disease Volume 197, Number 3, March 2009 Assessment and Course of ASD After MTBI TABLE 1. Participant Characteristics Across MTBI and GT Groups MTBI and ASD MTBI No ASD GT* and ASD GT No ASD N Age (14.18) (13.91) (9.85) (14.58) Male Female d in Hospital (16.49) (11.95) (14.8) (10.79) ISS (9.02) (9.2) 5.86 (3.81) 8.86 (6.22) GT indicates general trauma. T2, AQ:7 The interaction of length of PTA and ASD was examined in the MTBI group. To test for a difference in the prevalence of ASD according to length of PTA in the MTBI group, a log binomial regression model was fitted to the data. The result showed that there were no significant differences in prevalence of ASD according to PTA duration (chi square 6.53; p 0.16). A cross-tabulation of MTBI status and responses to each individual ASD symptom were calculated for the sample. To test for a difference in the prevalence of the reporting of each ASD symptom according to MTBI or non-mtbi group, a log binomial regression model was fitted to the data. This method was used as a comparison of each individual item on the CAPS between the general trauma and mild MTBI groups to determine p values for the individual symptoms Table 2 shows the rates of reporting of each individual symptom and the differences between the MTBI and non-mtbi groups. Significant differences were found between the groups in 5 of the 22 individual ASD symptoms. In each case, those with a MTBI reported higher symptoms than those without a MTBI. Of the ASD symptoms which were reported at significantly higher rates in the MTBI group, 3 of these were in the Dissociation cluster (reduced awareness, restricted affect and derealisation); and 1 in the Avoidance cluster (avoidance of people/places). The MTBI group reported significantly higher rates of impaired social functioning and subjective distress then those without a MTBI. DISCUSSION This study is one of the largest, multisited studies to investigate posttraumatic symptomatology after MTBI. It confirms previous research that ASD can develop after MTBI. The overall rate of ASD in the sample as a whole (3.42%), as well as the MTBI group (4.62%) and the non-mtbi group (2.47%) was considerably lower than the rate of 13% reported by previous researchers for ASD after MTBI (Harvey and Bryant, 1998). It is however consistent with other findings (O Donnell et al., 2004). It may be that methodological issues contributed the differences in prevalence rates. Most studies that find higher rates of ASD have used self report scales or the ASD Interview (Bryant et al., 1998) which has a simple dichotomous scoring scale. Studies using the CAPS in the past have tended to find lower levels of ASD (e.g., O Donnell et al., 2004). This maybe due to the rigor in which CAPS assesses symptoms. Our finding that the rate of subsyndromal ASD (16%) in our sample is similar to the ASD rate reported in other studies may support this hypothesis. The MTBI group diagnosed with ASD had the longest hospital stay (17.32 days on average). The remaining 3 groups did not differ significantly with mean hospital durations of 11 to 12 days after injury. The ISSs may account for some of the differences between groups as the non-mtbi groups (with and without ASD) had significantly lower ISSs than the MTBI groups. The MTBI/ASD and MTBI/NoASD groups, however, did not differ significantly on TABLE 2. Prevalence (%) of ASD Symptoms in MTBI and GT Groups ASD Cluster and Symptoms GT MTBI Re-experiencing % % Intrusive recollections Distressing dreams Recurrent thoughts Psychological distress Physiological reactivity Avoidance Avoidance thoughts/feelings Avoidance people/places * Arousal Sleep disturbance Irritability Concentration problems Hypervigilance Exaggerated startle response Dissociative Loss of interest Detachment Restricted affect Foreshortened future Derealisation Depersonalisation Reduced awareness Other Subjective distress Guilt Impaired social functioning *p p p values for comparisons of individual ASD symptoms between the general trauma patients and MTBI patients were adjusted for multiple comparisons using the stepdown Sidak method. ISS, which may suggest that psychological factors contributed to the length of stay in this MTBI group. In this current study, there was a trend for those with MTBI to be more likely to meet diagnostic criteria for ASD and significantly more likely to meet criteria for subsyndromal ASD. This finding may be associated with the overlap in symptoms between ASD and PCS. The majority of acute stress symptoms that the MTBI group scored more frequently relative to the non-mtbi group were symptoms which overlap between the diagnoses. Although the effect sizes were modest, the MTBI group scored higher on the ASD symptoms of restricted affect, derealisation and reduced aware Lippincott Williams & Wilkins 3

4 Broomhall et al. The Journal of Nervous and Mental Disease Volume 197, Number 3, March 2009 AQ:8 ness. Similarly, it is noteworthy that the MTBI group did not score more frequently on those symptoms that are recognized as the hallmark symptoms of PTSD and ASD, the re-experiencing cluster of symptoms. PCS may not be the only explanation for the significantly higher levels of psychological symptoms. Meares et al., (2006) also found that MTBI patients reported significantly higher levels of psychological symptoms. Several of the symptoms identified as ASD symptoms overlap with depressive symptoms (restricted affect, loss of interest). It is possible that in addition to postconcussion syndrome, depression played a role in the differences between the groups. Consistent with Meares et al., (2006), we found 2 symptoms were elevated in the MTBI patients over and above those overlapping ASD/PCS symptoms. The MTBI group reported higher levels of behavioral avoidance. This is noteworthy because high levels of avoidance in the acute setting may prevent emotional processing of the traumatic event and increase risk for later posttraumatic stress disorder (Foa et al., 1989). The other ASD symptom that the MTBI group scored more frequently was subjective distress. That is, the MTBI group found their symptoms significantly more distressing than did the non-mtbi group. It may be the case that the MTBI group was appraising their symptoms in such a way that it increased their distress. For example, high distress levels could be associated with misinterpretation of postconcussion/asd symptoms as indicating more serious organic pathology. If this is the case, it may increase the risk of poor long term psychological adjustment including the development of later PTSD. Specifically, it has been shown that negative cognitive appraisals of a situation are significantly linked to higher rates of PTSD after traumatic injury (Bryant and Guthrie, 2005). Around 20% of patients in each group reported intrusive recollections after the traumatic event. Although the MTBI group experienced either a loss of consciousness or period of PTA, it appeared that there had been a laying down of memory for some aspect of the event; a result which adds further evidence to the likelihood that posttraumatic symptoms are possible despite a MTBI. There are several possible mechanisms for the development of trauma symptomatology after MTBI. Individuals can develop memory for the traumatic event through piecing together information over time such as reports and photographs. It is also possible for the individual to possess islands of memory for the event, the lead up to the event and even of posttrauma events such as ambulance transfer to hospital. Further, although higher order conscious processes may be interrupted by a loss of consciousness, it is possible that subcortical processes particularly in the limbic system (involved in fear conditioning) can process the events of the trauma at an implicit level (Bryant, 2001). The present study faced a number of limitations. Although a number of studies have used the CAPS to diagnose ASD in the past, it is important to recognize that the CAPS was originally developed to diagnose chronic PTSD; how well it translates to the acute setting is unknown. Although the research focused on the development of ASD, the group contained patients whose symptoms may have resolved inside 1 month. Further, although the diagnosis of ASD was introduced as a marker for the development of PTSD, the group also contained patients who developed PTSD in the absence of ASD. Similarly assessing patients for posttraumatic stress symptoms in the acute hospital environment may have some confounding. For example, the finding that over 50% of participants experienced sleep difficulties may be a function of the hospital environment rather than a psychological disturbance. Finally, it is acknowledged that measures of cognitive functioning were not included in the current research. Future research would benefit from the inclusion of neuropsychological tests to clarify the incidence of cognitive impairment and relationship to posttrauma symptomatology. Given the considerable methodological overlap between ASD and postconcussion symptoms, attention toward the development of postconcussion symptoms after MTBI and their effect on posttrauma symptoms is also recommended. In conclusion, a significant level of psychological symptomatology is associated with the patients who experience ASD after MTBI. This may have implications on their later psychological adjustment and may suggest that those with MTBI are at risk for poor psychological adjustment. The prospective nature of this study will be able to inform this question at a later date. REFERENCES American Congress of Rehabilitation Medicine (1993) Definition of mild traumatic brain injury. J Head Trauma Rehabil. 8: Blake DD, Weathers FW, Nagy LM, Kaloupek DG, Charney DS, Keane TM (1998) Clinician-Administered PTSD Scale for DSM-IV. Boston (MA): National Center For Posttraumatic Stress Disorder. Bryant RA (2001) Posttraumatic stress disorder and mild brain injury: Controversies, causes and consequences. J Clin Exp Neuropsychol. 23: Bryant RA (2005) Predicting posttraumatic stress disorder from acute reactions. J Trauma Dissociation. 6:5 15. Bryant RA, Harvey AG (1998) Relationship between acute stress disorder and posttraumatic stress disorder following mild traumatic brain injury. Am J Psychiatry. 155: Bryant RA, Harvey AG (1999) The influence of traumatic brain injury on acute stress disorder and post-traumatic stress disorder following motor vehicle accidents. 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Brain Inj. 10: Ponsford J, Willmott C, Rothwell A, Cameron P, Kelly AM, Nelms R, Curran C, Ng K (2000) Factors influencing outcome following mild traumatic brain injury in adults. J Inte Neuropsychol Soc. 6: Sbordone RJ, Liter JC (1995) Mild traumatic brain injury does not produce post-traumatic stress disorder. Brain Inj. 9: Schnyder U, Moergeli H, Trentz O, Klaghofer R, Buddeberg C (2001) Prediction of psychiatric morbidity in severely injured accident victims at one-year follow-up. Am J Respir Crit Care Med. 164: Weathers FW, Keane TM, Davidson J (2001) Clinician-administered PTSD scale: A review of the first ten years of research. Depress Anxiety. 13: Weathers FW, Ruscio AM, Keane TM (1999) Psychometric properties of nine scoring rules for the Clinician-Administered Posttraumatic Stress Disorder Scale. Psycholog Assess. 11: Lippincott Williams & Wilkins

5 JOBNAME: AUTHOR QUERIES PAGE: 1 SESS: 1 OUTPUT: Tue Jan 13 11:47: /balt3/zkk nmd/zkk nmd/zkk00309/zkk z AUTHOR QUERIES AUTHOR PLEASE ANSWER ALL QUERIES 1 AQ1 Please check whether the short title provided is OK. AQ9 Please provide the division/department name for the first, second, and fourth affiliation. AQ10 Please provide the division/department name for the corresponding author. AQ2 Please list Rees, 2005 in the reference list. AQ3 Please list Frencham et al in the reference list. AQ4 Please check if changes made to (t 1, d 0.03, ns), ISS (t 1, d 1.1, ns), or age (t 1, d 1.8, ns) are OK. AQ5 Please list Baker et al., 1974 in the reference list. AQ6 Please expand DSM. AQ7 Please check whether the citations provided in the table footnote are OK. AQ8 Please list Bryant and Guthrie, 2005 in the reference list.