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TE is common and there is cross-national variation in prevalence. In the World Mental Health Survey (WMHS) (Kessler et al., 2017) with a combined sample of 68,894 adults across six continents,  findings showed that the highest TE prevalence estimates among high income countries was USA (83%); for all countries combined was 70%; 31% were exposed to four or more. Consistent across countries, five trauma types (i.e., witnessing death or serious injury, the unexpected death of loved one, being mugged, being in a life-threatening automobile accident, and experiencing a life-threatening illness or injury) accounted for over half of all exposures. The difference in prevalence across countries might be related to cultural variation, the examining method and whether indirect exposure type was included. Previous reviews indicated that the probability of PTSD associated with indirect exposure was lower than that for direct exposure (May & Wisco, 2016).

The community-based prevalence of PTSD varied among studies. In the U.S., a lifetime rate of 7% was identified (Kessler, Chiu, Demler, Merikangas, & Walters, 2005) compared with 0% in Zurich (Hepp et al., 2006). Besides the prevalence of full PTSD, variations of the condition were examined. In the Adult Psychiatric Morbidity Survey (APMS) conducted in U.K. (McManus, Meltzer, & Wessely, 2009), the estimate was about ‘probable PTSD’ (p-PTSD) based on the result of Trauma Screening Questionnaire (TSQ) (Brewin et al., 2002). Overall, 3% of adults screened positive for current p-PTSD.

There might be different factors contributing to the variation in rates of TE, as well as prevalence estimates of PTSD in different countries (e.g., the different age-ranges covered by different surveys). Findings based on national survey of a particular region or country have limited generalizability for another region.

PTSD was associated with a broad range of comorbid disorders. In a U.S. study, 88% of men and 70% of women with chronic PTSD met criteria for at least one other psychiatric disorder (Kessler, Sonnega, Bromet, Hughes, & Nelson, 1995). Studies which have examined comorbidity related to partial p-PTSD found intermediate levels of psychiatric comorbidity and functional impairment compared to trauma-exposed individuals without PTSD and those with full PTSD. These psychiatric disorders included mood, anxiety, substance use disorder, suicidal attempts and personality disorders (Jakupcak et al., 2007; Pietrzak, Goldstein, Southwick, & Grant, 2011). A meta-analysis of 63 studies found that a PTSD diagnosis was significantly associated with suicidality; the association persisted across studies using different measures of suicidality, current and lifetime PTSD, psychiatric and nonpsychiatric samples and PTSD populations exposed to different types of traumas (Panagioti, Gooding, & Tarrier, 2012). In U.K.’s APMS, current p-PTSD was strongly associated with psychosis, panic disorder or phobia, depressive episode, antisocial personality disorder, rs ≥ 0.61 (McManus et al., 2009). In the WMHS, 12-month PTSD associated with four or more traumatic events was correlated with greater comorbidity (i.e., mood and anxiety disorders) and greater functional impairment than other cases of PTSD (Karam et al., 2014). 

Our study examined epidemiology of traumatic experience (TE) and posttraumatic stress disorder (PTSD) among community dwelling Chinese adults in Hong Kong. Multistage stratification sampling design was used and 5,377 participants were included. In Phase-1, TE, probable PTSD (p-PTSD) and psychiatric co-morbid conditions were examined. In Phase-2, Structured Clinical Interview for the DSM-IV (SCID-I) was used for determining the weighted diagnostic prevalence of lifetime full PTSD. Disability level and health service utilization were studied. 

Findings showed that TE were common. The occurrence of direct TE among participants was  65%. When indirect TE types were included, the occurrence rate increased to 89%. Transportation accident (51%) was the most common TE. The prevalence of current p-PTSD among those with TE was 3%. Results of logistic regression suggested that 9 specific trauma types were significantly associated with p-PTSD. Among them, severe human suffering; sexual assault; unwanted or uncomfortable sexual experience; captivity; sudden and violent death had the greatest risks for developing PTSD. When compared to trauma controls, p-PTSD was associated with greater mental health burden in various parameters which included: i) 6 times higher rates for any past-week common mental disorder; ii) higher mental health service utilization, iii) poorer mental health indexes, and iv) greater disability.  

Our study is the first epidemiology study on the occurrence of traumatic experience and posttraumatic stress on a community level for Chinese in Hong Kong. The association of TE, PTSD and health service utilization found in this study suggested that both TE and PTSD should be considered public health concerns.


Brewin, C. R., Rose, S., Andrews, B., Green, J., Tata, P., McEvedy, C., . . . Foa, E. (2002). Brief screening instrument for post-traumatic stress disorder. British Journal of Psychiatry, 181, 158-162.

Hepp, U., Gamma, A., Milos, G., Eich, D., Ajdacic–Gross, V., Rössler, W., . . . Schnyder, U. (2006). Prevalence of exposure to potentially traumatic events and PTSD. The Zurich Cohort Study. European Archives of Psychiatry and Clinical Neuroscience, 256(3), 151-158.

Jakupcak, M., Conybeare, D., Phelps, L., Hunt, S., Holmes, H. A., & Felker, B. (2007). Anger, hostility, and aggression among Iraq and Afghanistan War veterans reporting PTSD and subthreshold PTSD. Journal of Traumatic Stress, 20, 945-954.

Karam, E. G., Friedman, M. J., Hill, E. D., Kessler, R. C., McLaughlin, K. A., Petukhova, M., & Kovess-Masfety, V. (2014). Cumulative traumas and risk thresholds: 12-month PTSD in the World Mental Health (WMH) surveys. Depression & Anxiety, 31(2), 130-142.

Kessler, R. C., Aguilar-Gaxiola, S., Alonso, J., Benjet, C., Bromet, E. J., Cardoso, F., . . . Collaborator, (2017). Trauma and PTSD in the WHO World Mental Health Surveys. European Journal of Psychotraumatology, (8:sup5, 1353383). Retrieved from  doi:10.1080/20008198.2017.1353383

Kessler, R. C., Chiu, W. T., Demler, O., Merikangas, K. R., & Walters, E. E. (2005). Prevalence, severity, and comorbidity of 12-month DSM-IV disorders in the National Comorbidity Survey Replication. Archives of General Psychiatry 62(6), 617-627.

Kessler, R. C., Sonnega, A., Bromet, E., Hughes, M., & Nelson, C. B. (1995). Posttraumatic stress disorder in the National Comorbidity Survey. Archives of General Psychiatry, 52(12), 1048-1060.

May, C. L., & Wisco, B. E. (2016). Defining trauma: How level of exposure and proximity affect risk for posttraumatic stress disorder. Psychological Trauma: Theory, Research, Practice, and Policy, 8(2), 233-240.

McManus, S., Meltzer, H., & Wessely, S. (2009). Posttraumatic stress disorder. UK: The Health & Social Care Information Centre, Social Care Statistics.

Panagioti, M., Gooding, P. A., & Tarrier, N. (2012). A meta-analysis of the association between posttraumatic stress disorder and suicidality: the role of comorbid depression. Comprehensive psychiatry, 53, 915-930.

Pietrzak, R. H., Goldstein, R. B., Southwick, S. M., & Grant, B. F. (2011). Prevalence and Axis I comorbidity of full and partial posttraumatic stress disorder in the United States: Results from Wave 2 of the National Epidemiologic Survey on Alcohol and Related Conditions. Journal of Anxiety Disorders, 25(3), 456-465.

Reference Article:

Wu, K. K., Leung, P. W., Wong, C. S., Yu, P. M., Luk, B. T., Cheng, J. P., Wong, R. M., Wong, P. P., Lui, J. C., Ngan, J. C., Leung, F. L. and Lam, L. C. (2019), The Hong Kong Survey on the Epidemiology of Trauma Exposure and Posttraumatic Stress Disorder. JOURNAL OF TRAUMATIC STRESS. doi:10.1002/jts.22430

Questions for Discussion:


About the Authors

Kitty Wu is a Senior Clinical Psychologist of the Hospital Authority of Hong Kong; the President of the Asian Society for Traumatic Stress Studies. She is the Principal Investigator for the Epidemiology Study of TE and PTSD in Hong Kong under the Division of Clinical Psychology, Hong Kong Psychological Society (DCP-HKPS).
Patrick Leung is a Professor of Psychology in the Chinese University of Hong Kong and Co-investigator for the Epidemiology Study of TE and PTSD in Hong Kong (DCP-HKPS).
Corine Wong is a Post-doctoral Fellow of the Department of Psychiatry of the University of Hong Kong and Co-investigator for the Epidemiology Study of TE and PTSD in Hong Kong (DCP-HKPS). She is a member of the Executive Committee of the Asian Society for Traumatic Stress Studies.