Harvard Program in Refugee Trauma, Massachusetts General Hospital, Harvard Medical School, Cambridge, Massachusetts, USA
Correspondence: David C. Henderson, MD, Harvard Program in Refugee Trauma, Massachusetts General Hospital, 22 Putnam Street, Cambridge, MA 02138, USA. Tel: (617) 876-7879; fax: (617) 496-2360; e-mail: dchenderson{at}partners.org
Funding detailed in Acknowledgements.
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ABSTRACT |
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Aims To examine the association between traumatic brain injury events and psychiatric symptoms of major depression and post-traumatic stress disorder (PTSD) in Cambodian survivors of mass violence.
Method The population comprised a multi-stage random sample of Cambodian refugees living in a Thai refugee camp. The main results analysed the relationship between six categories of trauma events and psychiatric symptoms of depression and PTSD during two time periods.
Results Almost 15 000 trauma events were reported (n=13 481, Pol Pot period; n=1249, past year). Traumatic brain injury was most common in the highly educated and in individuals with the highest levels of cumulative trauma. Of all trauma categories, traumatic brain injury revealed the strongest association with symptoms of depression, and a weaker association with PTSD. Brain injury represented 4% of the total number of traumatic events for both time periods, contributing 20% of the total symptom score for depression and 8% of that for PTSD.
Conclusions Clinical identification and treatment of traumatic brain injuries in highly traumatised populations must be maintained in order to develop a new public health model for their treatment.
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INTRODUCTION |
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The goal of this study was to examine the psychiatric effects of traumatic brain injury in a general civilian population that had experienced mass violence. The findings presented demonstrate the association between traumatic brain injury and the psychiatric symptomatology of major depression and post-traumatic stress disorder (PTSD) in a general population of Cambodian refugees who survived the Pol Pot regime of 1975-1979.
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METHOD |
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Sampling
Participants were selected by a multi-stage area sampling procedure that
randomly assigned 100 sampling points to Site 2's five sub-camps in proportion
to the numbers of households in each sub-camp
(Lynch, 1989). The
starting-place within each point and the order of points within sub-camps were
randomly assigned. When interviews were completed for ten households, a
sampling point was completed. At each household, the interviewer completed a
roster including the age and gender of each resident, and selected an adult
person of 18 years of age or more at random to be the respondent for the
household.
Assessment
The survey interviewers were volunteer residents of Site 2 with extensive
mental health experience. They were equally distributed by gender and received
4 days of training. Each interviewer was assigned randomly to primary sampling
units other than the one in which he/she resided. The interviews were
conducted in Cambodian and took an average of approximately 90 minutes. A
survey questionnaire (Mollica et
al, 1993), previously used in Khmer populations, was adapted
and translated specifically for this study. Translation methods were employed
to construct the final version of the interview schedule using the standard
methods of cross-cultural research
(Westermeyer, 1985;
Flaherty et al,
1988). This also included back-translation by experts in American
psychiatry and Khmer mental health.
The trauma history was derived from the Cambodian version of the Harvard Trauma Questionnaire (HTQ; Mollica et al, 1992). Measures of cumulative trauma were constructed from responses to questions about trauma events in Cambodia during the Pol Pot era and in Site 2 during the year before the interview (1989-1990). For each time period, affirmative responses were summed for 28 trauma events.
The 28 trauma events were grouped before analysis according to the kinds of trauma experienced as follows: (a) material deprivation (three events: lack of food or water, lack of shelter, and ill health without access to medical care); (b) warlike conditions (three events: combat situation, forced evacuation under dangerous conditions, shelling or grenade attacks); (c) definite traumatic brain injury (three events: beatings to the head, near-drowning, near-suffocation with a plastic bag); (d) bodily injury (four events: rape, torture, knifing or axing, beatings to other parts of the body); (e) coercion (seven events: imprisonment, brainwashing, being lost or kidnapped, forced labour, forced marriage, extortion or robbery by armed bandits); (f) violence to others (nine events: witnessing the murder of a family member or friend, witnessing the murder of a stranger, witnessing torture, witnessing rape, witnessing knifing or axing, witnessing beatings to any part of the body, witnessing a suicide attempt, witnessing near-drowning, witnessing near-suffocation with a plastic bag).
Symptom scales
Two interview schedules were used to measure psychological symptoms: a
25-item section of the Hopkins Symptom Checklist (HSCL-25;
Mollica et al, 1987)
and a 31-item section of the HTQ (Mollica
et al, 1992). The HSCL-25 was developed as a measure of
emotional distress. It comprises two sub-scales: a 10-item scale of anxiety
symptoms and a 15-item scale of depressive symptoms. The post-traumatic stress
symptom section of the HTQ consists of a scale made up of 16 of the 17
diagnostic criteria for PTSD (DSM-III-R and DSM-IV (American Psychiatric
Association, 1987, 1994)) which
measures symptoms of re-experiencing traumatic events, avoidance of stimuli
associated with the trauma, numbing of general responsiveness and increased
arousal. Physiological reactivity to events that symbolise or resemble the
traumatic event, a symptom of arousal in the DSM-III-R, was omitted because of
our inability to make appropriate physiological measurements.
The HTQ also includes a scale for culturally dependent symptoms, developed from clinical experience with Indochinese refugees, and a dissociation scale, scoring from 1 to 4 (high). In both schedules, respondents were asked to what extent they had been disturbed by each symptom during the past week.
Symptom scores for the HTQ and HSCL-25 are expressed as arithmetic means of these item-specific scores. Indochinese versions of the HSCL-25 and HTQ have been validated by the HPRT against clinical diagnoses in a sample of Indochinese refugee patients in a psychiatry clinic in the United States (Mollica et al, 1987, 1992), and in community samples of Vietnamese and Cambodian persons living in eastern Massachusetts (Caspi-Yavin, 1995). The psychometric properties of the Cambodian HSCL-2 and HTQ instruments have been well established (Mollica et al, 1987, 1992). The HSCL sub-scale of anxiety symptoms, a nonspecific measure that overlaps with many anxiety disorders, was not included in the analysis because it had not been validated in Cambodian populations with the DSM-III-R, DSM-IV, the Structured Clinical Interview for DSM-IV-TR Axis I disorders (SCID-I/P), ICD-9 or ICD-10 (World Health Organization, 1978, 1992).
Analysis
All analyses were conducted on the SAS System, Release 6.08 for
MicrosoftWindows (Cary, NC, USA). The main analyses were multiple linear
regression modelling with two terms for each of the six trauma categories, one
for trauma in the Pol Pot era and the other for trauma in the camp in the year
before interview (1989-1990). In addition, all models included terms for age,
years of education, marital status and gender. After the trauma categories
were created, a principal components factor analysis (with varimax rotation)
was conducted of the 28 trauma events. Five factors were identified. A
grouping of the trauma events by their highest factor loadings (all loadings
greater than 0.5) corresponded very closely to the a priori groupings
and gave empirical support to their construct validity.
The main results analysing the relationship between the effects of the six categories of trauma events and psychiatric symptoms were based upon the symptom scores derived from the depression sub-scale of the HSCL-25 and DSM-IV. These results are reported as linear regression coefficients (slopes) representing the estimated change in symptom scores for an increase of one event in each category of trauma. The precision of these estimates is reflected by 95% confidence intervals. The estimates may be viewed as measurements of the potency of each category of trauma on an event-by-event basis. Analyses were then conducted combining these point estimates with the frequency of reported trauma events, estimating the net effects of trauma events on psychiatric symptoms for each of the six trauma categories, and adjusting for group differences for each time period. Variables for age, education, marital status and gender were mean-centred.
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RESULTS |
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Tables 3 and 4 show the relationships between demographic characteristics and trauma in Site 2 during the year before interview. Each category of trauma events reveals a marked reduction in mean scores from the Pol Pot era trauma. Although there are some differences in the reporting of trauma events by demography, confidence intervals do not reveal significant differences within each trauma category, with the possible exception that respondents who had lost a spouse reported more material deprivation and warlike conditions. Traumatic brain injury events during this time period were not significantly different by demography although persons who had never been married reported less brain injury than did persons of any other marital status.
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Examining the relationship between cumulative trauma during the Pol Pot era and the relative frequency of each of the specific trauma categories, it is apparent that the different kinds of trauma were not uniformly distributed throughout the range of cumulative trauma. At low levels of cumulative trauma, traumatic brain injury events and bodily injury were relatively uncommon, while material deprivation, coercion and warlike conditions tended to predominate. At the highest levels of cumulative trauma, the proportional frequency of material deprivation was greatly reduced; coercive trauma remained relatively high and traumatic brain injury and bodily injury rose to prominence. Thus, brain and bodily injury were disproportionately common among persons who experienced large numbers of trauma events overall.
The point estimate or relative potency for the different categories of trauma are shown in Table 5 for depressive symptoms and in Table 6 for the criterion symptoms of PTSD. The point estimates are much more precise for the more frequent trauma in the Pol Pot era than during the year before the interview, as reflected in the relative widths of the confidence intervals. The relationships between categories of trauma and symptoms of depression and PTSD are graphically illustrated in Figs 1a and 2a and 1b and 2b, respectively. For depressive symptoms, consistently strong associations with traumatic brain injury are apparent in both time periods. Depressive symptoms are also strongly associated with material deprivation in the year before the interview. For PTSD symptoms, the association with trauma categories is weaker. The strongest associations with this measure of symptomatology are between traumatic brain injury and coercion in both time periods (Figs 2a and b) and with material deprivation in the camp in the year before interview (Fig. 2b).
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Almost 15 000 separate trauma events were reported in the two time periods (Tables 5 and 6); over 90% (13 481/14 730=92.5%) of these events were experienced in the Pol Pot era. As Tables 5 and 6 show, the frequency of the different categories of trauma during each of the time periods when combined with their estimated potencies (point estimates) and adjusted for group differences reveals the net contribution of each trauma category to the total symptom scores of depression and PTSD. For both measures, approximately 450 symptom units were the net contribution of all trauma events to the estimated baseline symptom score that would have been present in the hypothetical absence of trauma. For depressive symptoms (Table 5), coercive trauma during the Pol Pot era (n=2853 events) had the greatest effect, contributing 198.4 symptom units or 45% of the total. In contrast, traumatic brain injury events, although six times less frequent than coercion during the Pol Pot era (n=551 events), contributed 83.1 symptom units or almost 20% of the total symptom score for depression. For PTSD symptoms, coercive events during the Pol Pot era again had the greatest effect, contributing 223.3 symptom units or almost 50% of the total; traumatic brain injury events contributed 33.1 symptom units or 7.4%. Similar patterns exist for PTSD and depression for the refugee camp period, reflecting a smaller net contribution of brain injury to the symptoms of PTSD and depression because there were only 16 brain injury events.
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DISCUSSION |
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The Cambodian respondents in our survey reported numerous episodes of head trauma severe enough to be associated with underlying brain injury by a number of described mechanisms (Courville, 1937; Ommaya & Gennarelli, 1974; Kwentus et al, 1985; Mesulam, 1986). Our results suggest that traumatic brain injury events can lead to considerable psychiatric sequelae up to 10 years after the events have occurred. It is our hypothesis that the psychiatric effects from traumatic brain injury events described in traditional populations will be at least as severe in refugees, because of their compromised physical and mental status (Mollica & Jalbert, 1989; Reynell, 1989). Because of the latter, refugee survivors of traumatic brain injury events might be especially vulnerable to psychiatric disorders. For example, a mild head injury event which had occurred during the Pol Pot era might lead to symptoms of depression (Robinson & Szetela, 1981). Depressive symptoms and neurocognitive deficits might diminish the refugees' ability to cope with their new social realities, such as refugee camp life in Site 2. Investigations of neurocognitive changes and accompanying psychiatric symptoms in traditional traumatic brain injury research have shown that the psychiatric effects of traumatic brain injury only worsen with poor social performance and limited social supports (Jennett & Teasdale, 1981; Dikmen et al, 1983, 1986, 1994, 1995, 1996). This process may be of special concern in refugee populations where there is no recognition of the refugees' underlying traumatic brain injury events.
Our findings are consistent with recent work suggesting that the self-report of head injury is a risk factor for depression and the severity of depression in combat-exposed veterans (Vasterling et al, 2000). The effect of head injury appeared also to be associated with PTSD but to a lesser degree; head injury predicted depression but not PTSD severity.
Limitations
A number of major limitations affect the validity of our
hypothesis-building and interpretation of study results. The traumatic brain
injury events in this study are based upon self-reports; the number of
individual traumatic brain injury events and estimates of the severity of
possible injury, were not obtained. Information regarding post-concussive
states and objective evidence, such as neuroimaging and neuropsychological
testing, of the traumatic brain injury experiences were not obtained.
Torturers and perpetrators of mass violence rarely leave records of their
actions that can be compared with respondents' reports. The general issues
relating to the accuracy of these reports of trauma events have been presented
in two major reviews (Mollica &
Caspi-Yavin, 1991; Willis,
1998). However, considerable attention was directed in this study
to determining the accuracy of respondents' self-reports of trauma (Mollica
et al, 1993,
1998a,
b).
The relationship between traumatic brain injury events and specific neuropsychiatric sequelae was not established in this study. Neuropsychiatric assessments of each respondent might have revealed the neurocognitive deficits associated with traumatic brain injury events; the latter would have also helped establish the accuracy of self-reporting of traumatic brain injury events. The danger of interviewing the residents of Site 2 (which was in a war zone) as well as the limited applicability of culture-fair neuropsychological tests (with none currently validated for Cambodian populations) prevented an adequate assessment of potential traumatic brain injury effects (Manuel-Dupont et al, 1992). Finally, the relationships between social support and the resiliency to head injury need to be further evaluated and established (Mollica et al, 2002).
Future studies
Future prospective studies which begin closer to the initial period of
victimisation will also help disentangle the relationship between traumatic
brain injury events and traumatic brain injury effects (psychiatric symptoms
and neurocognitive deficits) and their impact on social performance over
time.
Culturally validated methods for the clinical evaluation of traumatic brain injury in survivors of mass violence have not been clarified. Approaches for disentangling the complicated clinical symptomatology of comorbid post-concussive syndrome, depression and PTSD have not been adequately researched. Further studies are needed to clarify the relative impact of traumatic brain injury and psychiatric, social and economic disability. It is possible that survivors of mass violence with traumatic brain injuries are the most chronically disabled psychiatric patients and the most difficult to treat.
Traumatic brain injury, depression and PTSD
Early identification of depression and PTSD together with possible
traumatic brain injury is very important in the assessment of torture
survivors and highly traumatised populations. Traumatic brain injury has
potent effects and has an impact on neuro-psychological deficits and the
course of illness, and may be associated with or even masked by depression
(Weinstein et al,
2001). If a traumatic brain injury is found, a neurocognitive
evaluation (neurological examination, neuropsychological testing and
neuroimaging studies) must be performed to determine the extent of the
deficits. In a refugee camp, where neuropsychological testing is rarely
available, an assessment of social and physiological functioning is
important.
The psychological horror of mass violence combined with the physical damage of traumatic brain injury may have long-term negative medical and psychiatric effects on many survivors. These effects, however, can be ameliorated if there is proper recognition of their causes and consequences.
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Clinical Implications and Limitations |
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LIMITATIONS
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ACKNOWLEDGMENTS |
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Received for publication November 6, 2001. Revision received June 14, 2002. Accepted for publication June 14, 2002.