@article {karam_cumulative_2014,
	title = {Cumulative traumas and risk thresholds: 12-month PTSD in the World Mental Health (WMH) surveys},
	journal = {Depression and Anxiety},
	volume = {31},
	number = {2},
	year = {2014},
	month = {feb},
	pages = {130{\textendash}142},
	abstract = {BACKGROUND: Clinical research suggests that posttraumatic stress disorder (PTSD) patients exposed to multiple traumatic events (TEs) rather than a single TE have increased morbidity and dysfunction. Although epidemiological surveys in the United States and Europe also document high rates of multiple TE exposure, no population-based cross-national data have examined this issue. METHODS: Data were analyzed from 20 population surveys in the World Health Organization World Mental Health Survey Initiative (n = 51,295 aged 18+). The Composite International Diagnostic Interview (3.0) assessed 12-month PTSD and other common DSM-IV disorders. Respondents with 12-month PTSD were assessed for single versus multiple TEs implicated in their symptoms. Associations were examined with age of onset (AOO), functional impairment, comorbidity, and PTSD symptom counts. RESULTS: 19.8\% of respondents with 12-month PTSD reported that their symptoms were associated with multiple TEs. Cases who associated their PTSD with four or more TEs had greater functional impairment, an earlier AOO, longer duration, higher comorbidity with mood and anxiety disorders, elevated hyperarousal symptoms, higher proportional exposures to partner physical abuse and other types of physical assault, and lower proportional exposure to unexpected death of a loved one than cases with fewer associated TEs. CONCLUSIONS: A risk threshold was observed in this large-scale cross-national database wherein cases who associated their PTSD with four or more TEs presented a more "complex" clinical picture with substantially greater functional impairment and greater morbidity than other cases of PTSD. PTSD cases associated with four or more TEs may merit specific and targeted intervention strategies.},
	keywords = {Adolescent, Adult, Age of Onset, Child, Comorbidity, Epidemiology, Europe, Female, functional impairment, Health Surveys, Humans, Internationality, Life Change Events, Male, Mental Disorders, Post-Traumatic, Prevalence, Psychological, PTSD, Risk Factors, STRESS, Stress Disorders, United States, World Mental Health Surveys, Young Adult},
	issn = {1520-6394},
	doi = {10.1002/da.22169},
	author = {Karam, Elie G. and Friedman, Matthew J. and Hill, Eric D. and Ronald C. Kessler and McLaughlin, Katie A. and Petukhova, Maria and Sampson, Laura and Shahly, Victoria and Angermeyer, Matthias C. and Bromet, Evelyn J. and Girolamo, Giovanni de and de Graaf, Ron and Demyttenaere, Koen and Ferry, Finola and Florescu, Silvia E. and Haro, Josep Maria and He, Yanling and Karam, Aimee N. and Kawakami, Norito and Kovess-Masfety, Viviane and Medina-Mora, Mar{\'\i}a Elena and Browne, Mark A. Oakley and Posada-Villa, Jos{\'e} A. and Shalev, Arieh Y. and Stein, Dan J. and Viana, Maria Carmen and Zarkov, Zahari and Koenen, Karestan C.}
}
