Elsevier

The Lancet

Volume 360, Issue 9339, 5 October 2002, Pages 1056-1062
The Lancet

Articles
Long-term effect of psychological trauma on the mental health of Vietnamese refugees resettled in Australia: a population-based study

https://doi.org/10.1016/S0140-6736(02)11142-1Get rights and content

Summary

Background

What are the deleterious effects of mass trauma on the psychological wellbeing of refugees and other war-affected populations? Most epidemiological data are for short-to-medium term effects, leaving the possibility that early psychological reactions could reduce naturally over time. We aimed to assess the long-term effects of trauma on mental health and disability in Vietnamese refugees resettled in Australia.

Methods

In a population-based study, we identified a community sample of 1413 adult Vietnamese from census collection areas in Sydney, Australia. Participants were interviewed by trained bilingual workers who administered questionnaires to assess the frequency of international classification of disease, version 10 (ICD-10) mental disorders in the 12 months before interview; psychiatric symptoms, by use of a culturally-sensitive symptom measure; exposure to psychologically traumatic events; disability and use of health services; and social, economic, and cultural factors since migration. We did multivariate analyses with adjustment for stressors since migration to establish the risk factors for mental illness.

Findings

1161 (82%) adults completed the interview. Mean length of residence in Australia was 11·2 years (SD 14·4) and mean time since the most severe traumatic event was 14·8 years (SD 10·8). 95 (8%) and 75 (7%) of participants had mental disorders defined by ICD-10 and the culturally-sensitive measure, respectively. Trauma exposure was the most important predictor of mental health status. Risk of mental illness fell consistently across time. However, people who had been exposed to more than three trauma events (199) had heightened risk of mental illness (23, [12%]) after 10 years compared with people with no trauma exposure (13, [3%]) (odds ratio 4·7, p<0·0001, 95% Cl 2·3–9·5).

Interpretation

Most Vietnamese refugees were free from overt mental ill health. Trauma-related mental illness seemed to reduce steadily over time, but a subgroup of people with a high degree of exposure to trauma had long-term psychiatric morbidity. Our findings support the need to develop specialised mental health services to reduce disability in refugees whose exposure to extreme trauma puts them at risk of chronic psychiatric disability.

Introduction

Adverse psychiatric consequences of psychologically traumatic events (trauma) have been reported in refugee populations,1, 2, 3 but the extent and implications of such mental health effects are unclear.4, 5 Whether or not psychological trauma has a deleterious effect on mental function is a critical issue in public health at a time when war, conflict, and terrorism affect more than 100 countries worldwide. From a human rights perspective, an exaggeration of the mental health effect of trauma will risk medicalising, and potentially stigmatising, survivors. At the other extreme, an underestimation of the mental health consequences of mass trauma might lead to neglect of the legitimate care needs of some survivors.

Empirical data in published reports pertain mainly to the short-to-medium-term effects of mass trauma and displacement. Epidemiological studies have identified post-traumatic stress disorder and depression as the two most prevalent disorders in refugee populations. These categories of illness seem to be identifiable, with some variation, across cultures.6, 7, 8, 9 A robust dose-response association has emerged from several studies in which cumulative exposure to trauma has been linked with a progressively increasing risk of psychiatric morbidity.6, 10, 13 Furthermore, depression is one of the main contributors to the global burden of disease, and post-traumatic stress disorder has a smaller but appreciable role.14 The rates of these two disorders are higher in refugee than in non-refugee populations, which suggests that exposure to mass trauma might be a major factor in psychological disability worldwide.7, 9, 15

Despite this evidence, suggestions have been made that the issue of mass trauma in non-western populations exposed to war has been exaggerated, and that the need for specialised mental health interventions for refugees has been overstated.5, 16, 17 A key issue is whether psychological reactions to trauma persist over time and whether such reactions in refugees can become disabling. Most studies have been undertaken quite soon after refugee communities have been exposed to trauma, and usually in conditions of abnormal stressors—eg, in refugee camps or soon after arrival in countries of resettlement. A few longitudinal studies have been done, but only for 3-year follow-up periods.18, 20 Although results of an epidemiological study undertaken in a non-refugee setting suggested a steady decline in risk of post-traumatic stress disorder during the 6 years after a traumatic incident, a subgroup of people showed mental health difficulties that persisted beyond that time.21

After the communist victories in 1975, more than 2 million people fled from Indochina (Vietnam, Cambodia, and Laos) to western countries, and three-quarters of these were from Vietnam. The number of Vietnamese refugees resettled in Australia grew from less than 1000 in 1975 to more than 150 000 in 1996. This migration was followed by a period of family reunion.22 Because a long period of time has elapsed since the arrival of most Vietnamese refugees in Australia, we have been able to investigate the long-term effect of trauma on a group that is now resettled in a stable environment.

We aimed to assess the long-term mental health outcomes in refugee populations by ascertaining the proportion who had disabling mental health problems years after resettlement, and establishing the role of trauma in these residual disorders. We have investigated the effect of trauma on common emotional disorders and associated indices of disability in Vietnamese refugees resettled in Australia.

Section snippets

Participants

We identified small census collection areas across five local-government areas in New South Wales, Australia, that included 71% of all Vietnamese-born residents (Vietnamese Australians) in the state. We used a probability proportional-to-size cluster sampling method to select 44 census collection areas, with a density of Vietnamese-Australians of between 2% and 45%. We identified households with at least one person of Vietnamese origin and invited one person per household to participate. We

Results

The mean number of Vietnamese Australians living in each census area was 130 (SD=106). Of 6224 private dwellings approached, 1413 households had at least one person of Vietnamese origin. 1161 (82%) of eligible households participated in the survey. Estimates of internal consistency ranged from 0·87 to 0·95 for the three scales; test-retest reliability coefficients during 4 days ranged from 0·81 to 0·89. All participants understood Vietnamese (99%) or English (1%) to a sufficient level to

Discussion

Our findings show that, although a mean of 14 years had elapsed since exposure to the most distressing traumatic event (index trauma), a significant association persisted between trauma exposure and risk of mental illness, whether defined by western or culturally-appropriate criteria. Trauma showed a dose-response relation with mental ill health and with indices of psychosocial dysfunction, a finding that lends support to research undertaken in refugee groups from diverse cultural backgrounds.10

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