Prevalence, predictors and associations of complex post-traumatic stress disorder with common mental disorders in refugees and forcibly displaced populations: a systematic review

Figures & data

Figure 1. PRISMA flow diagram of the study selection and inclusion process

Table 1. Formulation of CPTSD and outcome measure

	Formulation and outcome measures
	DESNOS	CPTSD
Author, year published	SIDES^i	SIDES-SR^ii	ITQ^iii	CTD Measure^i	Unique to the study
Al-Rasheed (2004)		1
De Jong et al. (2005)	1
Teodorescu et al. (2012)	1
Dokkedah et al. (2015)			1
Tay et al. (2015)					1^i
Nickerson et al. (2016)					1^ii
Al Ibraheem et al. (2017)				1
Kira et al. (2017)				1
Hecker et al. (2018)			1
Hoffman et al. (2018)			1
Hyland et al. (2018)			1
Silove et al. (2018)					1^i
Frost et al. (2019)					1 ^ii

DESNOS: Disorder of extreme stress not otherwise specified; CPTSD: Complex post-traumatic stress disorder; SIDES: Structured interview for disorders of extreme stress; SIDES-SR: Self report version of SIDES; ITQ: International Trauma Questionnaire; CTD: Cumulative trauma disorders.

Superscript indicates the type of measure: ⁱ Structured diagnostic/clinical interview; ⁱⁱ Self report symptom checklist; ⁱⁱⁱ Standardised questionnaire.

Table 2. Prevalence according to the different formulations by country of origin and assessment

Country of origin	Country of assessment	CPTSD prevalence	DESNOS prevalence	Sample size (N)	Author, year published	Study population type	Diagnostic timeframe
Africa
Ethiopia	Ethiopia		2.2%	1200	De Jong et al. (2005)	Random sample in refugee camp	Not stated
Algeria	Algeria		13.2%	652	De Jong et al. (2005)	Random sample from a settled community affected by recent terrorism	Not stated
Uganda	Uganda	15.0%		314	Dokkedah et al. (2015)	Principles of random sampling used in community survivors of war (lack of national register)	Not stated
Middle East
Kuwait	Kuwait	85.8%		900	Al-Rasheed (2004)	Random sample using civil register of female survivors of war	Lifetime and current combined
Gaza	Gaza		5.6%	585	De Jong et al. (2005)	Random sample of long-term refugee population with ongoing conflict	Not stated
Syria	Syria and Netherlands	40.0%		306	Al Ibraheem et al. (2017)	One snowball sample of resettled refugees, and the other a sample of IDPs in Syria	Not stated
Syria	Egypt	47.0%		196	Kira et al. (2017)	Snowball sample of Syrian refugees in Egypt	Not stated
Syria	Lebanon	36.1%		110	Hyland et al. (2018)	Convenience sample of treatment seeking Syrian refugees in Lebanon	Past one month
Iraq and Syria	Kurdistan	50.9%		108	Hoffman et al., 2018 (Hoffman et al., 2018)	Convenience sample from four refugee camps	Not stated
Asia Pacific
West Papua	Papua New Guinea	3.0%		250	Tay et al. (2015)	Random sample of refugees based on community survey	Not stated
West Papua	Papua New Guinea	9.3%		487	Silove et al. (2018)	Random sample of refugees based on census data	Not stated
Mixed countries
Group A	Norway		16% (82% lifetime)	61	Teodorescu et al. (2012)	Convenience sample of treatment seeking resettled refugees	Lifetime and current separately
Group B	Switzerland	33.0%		152	Nickerson et al. (2016)	Convenience sample of treatment seeking resettled refugees	Not stated
Group C	Switzerland	21.3%		98	Hecker et al. (2018)	Convenience sample of those seeking treatment and utilising other refugee resettlement support services	Past one month
Group D	USA	4.9%		308	Frost et al. (2019)	Retrospective, based on nation-wide survey in USA, those who endorsed refugee status	Not stated

CPTSD: Complex post-traumatic stress disorder; DESNOS: Disorder of extreme stress not otherwise specified.

Group A:Eastern Europe, Africa, Middle East, Far East, Latin America; Group B Turkey, Iran, Sri Lanka, Bosnia, Iraq, Afghanistan; Group C: Syria, Afghanistan, Eritrea, Turkey, Iraq, North Africa, Sub-Saharan Africa; Group D: European, Asian, South American, African, North American.

Table 3. Predictors associated with CPTSD

Predictor/Study	Specific predictor studied	Statistical test	Result	Sample size (n)	Association
Trauma type
Al-Rasheed (2004)	Armed conflict trauma	Pearson’s Correlation	r = 0.115, p < 0.10	900	Yes
	War zone trauma	Pearson’s Correlation	r = 0.222, p < 0.10	900	Yes
Dokkedah et al. (2015)	Personal Injury	One-way ANOVA	F = 2.51, p < 0.01	314	Yes
	Witnessing Violence	One-way ANOVA	F = 1.54, p < 0.05	314	Yes
	Deaths	One-way ANOVA	F = 1.84, p < 0.01	314	Yes
	Participating in Armed Groups	One-way ANOVA	F = 1.71, p < 0.01	314	Yes
	Sexual Abuse	One-way ANOVA	F = 1.59, p < 0.01	314	Yes
Tay et al.(2015)	Witnessing murder	MIMIC analyses	Beta: Intrusion = 0.77, p < 0.01; Avoidance = 0.65, p < 0.05	250	2 of 6#
	Interaction: witnessing murder x injustice	MIMIC analyses	Beta: Intrusion = 0.05, p < 0.05; Avoidance = 0.65, p < 0.05	250	2 of 6#
Al Ibraheem et al. (2017)	Syrian Oppressive Experience	Zero order correlation	r = 0.25, p < 0.001	306	Yes
Hyland et al.(2018)	Forced displacement	Multinomial logistic regression	OR (95% CI) = 6.01 (0.80–45.08)	110	No
Silove et al. (2018)	Persecution and displacement	Hierarchical linear regression analysis	β = 0.24, p < 0.01	447	Yes
	Childhood trauma and adversity	Hierarchical linear regression analysis	β = 0.05, p < 0.001	417	Yes
Frost et al.(2019)	Physical abuse	Multinomial logistic regression analysis	OR = 7.42	308	Yes
	Neglect	Multinomial logistic regression analysis	OR = 15.02	308
	Sexual assault	Multinomial logistic regression analysis	OR = 7.6	308
	Serious accident	Multinomial logistic regression analysis	OR = 3.53; p < 0.001	308
Trauma count
Teodorescu et al. (2012)	Number and types of traumatic events	Kendall’s tau-b Correlation Coefficient	r = 0.326, p < 0.05	61	Yes
Hecker et al. (2018)	Number of traumatic event types	Multiple regression	B = 0.59, SE = 0.53, beta = 0.11, t = 1.13, p > 0.05	98	No
Frost et al. (2019)	Two traumas	Multinomial logistic regression	OR = 5.81	308	Yes
	Three traumas	Multinomial logistic regression	OR = 19.93	308
	Four traumas	Multinomial logistic regression	OR = 29.62; p < 0.001	308
Gender
Dokkedah et al. (2015)		Chi squared	χ2 = (1, n = 308) = 0.86, p = 0.35.	M = 160, F = 154	No
Tay et al.(2015)		MIMIC analyses	No significant association	M = 137 F = 93	No
Hecker et al. (2018)		Multiple regression	B = 5.54, SE = 4.46, beta = 0.12, t = 1.24, p > 0.05	98	No
Hyland et al. (2018)		Chi squared	χ2 = 0.31, df = 1, p = 0.578, OR = 1.31	110	No
Frost et al. (2019)		Multinomial logistic regression analysis	OR = 10.49, p < 0.001	308	Yes
Lack of social support/PMLDs
Hecker et al. (2018)	Perceived lack of social support in host country	Multiple regression	B = 0.56, SE = 0.24, beta = 0.22, t = 2.35, p < 0.05	98	Yes
Hecker et al. ()	PMLDs	Multiple regression	B = 0.63, SE = 0.15, beta = 0.42, t = 4.36, p < 0.001	98	Yes
Silove et al. (2018)	PMLDs	Hierarchical linear regression analysis	β = 0.16, p < 0.01	487	Yes
Hoffman et al. (2018)	Stress endured in post-ISIS camps	Post-hoc Bonferroni test	no PTSD = 2.45, PTSD = 2.77, CPTSD = 3.78; p < 0.0001	108	Yes

CPTSD: Complex post-traumatic stress disorder; MIMIC: Multi-Indicators-Multiple-Causes; M: Male, F: Female; #2 out of 6 symptoms associated, not overall; p > 0.5 No significant association;

PMLDs Post-migration living difficulties.

Table 4. Association between CPTSD and CMDs

Study	Statistical test	Result	Sample size (n)	Association
PTSD
Al-Rasheed (2004)	Pearson’s correlation	r = 0.222, p < 0.01	900	Yes
Nickerson et al. (2016)	Correlation	Correlations between CPTSD and PTSD subscales r values ranged between 0.24–0.48, p < 0.001p<0.001	152	Yes
Kira et al. (2017)	Zero-order correlation	r = 0.60, p < 0.001	196	Yes
Tay et al. (2015)	MIMIC analyses	Beta: Intrusion = 0.77, p < 0.01; Avoidance = 0.65, p < 0.05	250
Depression and anxiety
Dokkedah et al. (2015)	Pearson correlation: depression/anxiety combined	r = 0.32–0.68, p < 0.01 for all CPTSD domains	314	Yes
Somatisation
Dokkedah et al. (2015)	Pearson correlation	r = 0.26–0.46, p < 0.01 for all CPTSD domains	314	Yes

CPTSD: Complex post-traumatic stress disorder; CMDs: Common mental disorders.

Table A1. Search strategy for PsycINFO database

Search Strategy: Database: PsycINFO <1987 to August Week 1 2017> Search for: from 52 [limit 51 to english language] keep 1–77; Results: 77

1 complicated PTSD.ab. or complicated PTSD.ti. (WHO, 1992)

2 complex PTSD.ab. or complex PTSD.ti. (308)

3 complex post?traumatic stress disorder*.ab. or complex post?traumatic stress disorder*.ti. (170)

4 complex post traumatic stress disorder*.ab. or complex post traumatic stress disorder*.ti. (60)

5 complicated post?traumatic stress disorder*.ab. or complicated post?traumatic stress disorder*.ti. (Herman, 1992)

6 complicated post traumatic stress disorder*.ab. or complicated post traumatic stress disorder*.ti. (Chodoff, 1968)

7 C?PTSD.ab. or C?PTSD.ti. (87)

8 enduring personality change after catastrophic experience.ab. or enduring personality change after catastrophic experience.ti. (Brewin et al., 2017)

9 EPCACE.ab. or EPCACE.ti. (Dokkedah et al., 2015)

10 (disorders of extreme stress not otherwise specified).ab. or (disorders of extreme stress not otherwise specified).ti. (Tay et al., 2020)

11 DESNOS.ab. or DESNOS.ti. (54)

12 exp Posttraumatic Stress Disorder/(27440)

13 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8 or 9 or 10 or 11 or 12 (27528)

14 refugee*.ab. or refugee*.ti. (5996)

15 asylum.ab. or asylum.ti. (2228)

16 displaced.ab. or displaced.ti. (3339)

17 hostage*.ab. or hostage*.ti. (483)

18 prisoner*.ab. or prisoner*.ti. (6634)

19 torture*.ab. or torture*.ti. (2261)

20 war.ab. or war.ti. (21607)

21 warfare.ab. or warfare.ti. (1195)

22 armed conflict*.ab. or armed conflict*.ti. (820)

23 mass conflict*.ab. or mass conflict*.ti. (Grossman et al., 2019)

24 civil conflict*.ab. or civil conflict*.ti. (154)

25 persecut*.ab. or persecut*.ti. (2712)

26 genocide.ab. or genocide.ti. (1373)

27 holocaust.ab. or holocaust.ti. (2371)

28 mass murder.ab. or mass murder.ti. (216)

29 terrorism.ab. or terrorism.ti. (4518)

30 bioterrorism.ab. or bioterrorism.ti. (208)

31 human rights.ab. or human rights.ti. (6092)

32 ethnic cleansing.ab. or ethnic cleansing.ti. (130)

33 refugees/(4646)

34 Asylum Seeking/(337)

35 WAR/(10336)

36 exp PRISONERS/(8196)

37 prisoner abuse/(48)

38 HOSTAGES/(193)

39 exp GENOCIDE/(1971)

40 Mass Murder/(94)

41 exp TERRORISM/(6809)

42 TORTURE/(1139)

43 PERSECUTION/(343)

44 exp Human Rights/(10,582)

45 14 or 15 or 16 or 17 or 18 or 19 or 20 or 21 or 22 or 23 or 24 or 25 or 26 or 27 or 28 or 29 or 30 or 31 or 32 or

33 or 34 or 35 or 36 or 37 or 38 or 39 or 40 or 41 or 42 or 43 or 44 (68,588)

46 13 and 45 (4934)

47 limit 46 to english language (4646)

48 limit 47 to yr = ‘2008 -Current’ (2252)

49 complex ptsd/or desnos/(153)

50 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8 or 9 or 10 or 11 or 49 (583)

51 45 and 50 (87)

52 limit 51 to english language (77)

53 exp *Posttraumatic Stress Disorder/(23,601)

54 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8 or 9 or 10 or 11 or 53 (23,736)

55 45 and 54 (4186)

56 from 52 keep 1–77 (77)

Table A2. Example of critical appraisal checklist completed for one study

JBI Critical Appraisal Checklist for Studies Reporting Prevalence Data Reviewer RM Date 21/10/17 Author Teodorescu et al. Year 2012 Record Number#15530
	Yes	No	Unclear	Not applicable
(1) Was the sample frame appropriate to address the target population? Refugees in Norway in outpatient treatment who speak Norwegian	□	□	□	□
(2) Were study participants sampled in an appropriate way? Psychiatric outpatients referred by GP	□	□	□	□
(3) Was the sample size adequate? n = 63	□	□	□	□
(4) Were the study subjects and the setting described in detail? Yes	□	□	□	□
(5) Was the data analysis conducted with sufficient coverage of the identified sample? 61/63	□	□	□	□
(6) Were valid methods used for the identification of the condition? SIDES, only validated in Western populations	□	□	□	□
(7) Was the condition measured in a standard, reliable way for all participants? One researcher conducted interviews after undergoing extensive training.	□	□	□	□
(8) Was there appropriate statistical analysis? Yes	□	□	□	□
(9) Was the response rate adequate, and if not, was the low response rate managed appropriately? 57/63	□	□	□	□

Overall appraisal: Include□Exclude□Seek further info □ Comments (Including reason for exclusion)

Table A3. Details of the 19 studies that met inclusion criteria

Reference	Sample characteristics	Outcome measure CPTSD	Type of measure^1 CPTSD	Outcome measure DESNOS	Type of measure^a DESNOS	Sample size	Response rate n (%)	Age range	% female	Living status^b	Time since conflict or resettlement (years)	Trauma measure	Trauma count	Prevalence CPTSD	Prevalence DESNOS
Weine et al. (1998)	A convenience sample of Bosnian refugees resettled in Connecticut, obtained through referral by unspecified refugee resettlement agencies	N/A	N/A	SCID-DES	3	31	24/31 (77.4%)	13–59	50%	6	1 year since resettlement, 2–3 years since conflict	“ethnic cleansing”	Not stated	N/A	Zero
Al-Rasheed (2004)	A random, stratified sample of Kuwaiti women identified using a civil database, exposure to war trauma was considered a universal experience	SIDES-SR. Definition based on literature by Herman (Herman, 1992).	1	N/A	N/A	900	683 (75.9%)	18–55	100%	1	13 years −1990 Iraqi invasion (concern that the 2003 war in Iraq may have affected)	Trauma Exposure Inventory-I & Trauma Exposure Inventory-II	2240	85.8% (lifetime)	N/A
De Jong et al. (2005)	Epidemiological survey using multistep random sampling procedures using addresses to select samples from three populations: Algeria, settled community affected by recent terrorism; Ethiopia, refugee camps; Gaza, long term refugee population affected by ongoing conflicts	N/A	N/A	SIDES	1	n = 652 (Algeria), n = 1200(Ethiopia), n = 585(Gaza)	Algeria (76.7%), Ethiopia (99%), Gaza (98%)	Algeria (mean 40.6, SD 20.6), Ethiopia (mean 33.9, SD 9.9), Gaza (mean 31.6, SD 11.6)	Algeria 45.7%, Ethiopia 62.4%, Gaza 53.2%	Algeria (Chodoff, 1968), Ethiopia (Roth et al., 1997), Gaza (Roth et al., 1997)	Not stated	Adapted version of the Life Events and Social History Questionnaire; 9 trauma types described (de Jong et al., 2001)	Not stated	N/A	Algeria 13.2%, Ethiopia 2.2%, Gaza 5.6%
Morina and Ford (2008)	A random sample using ‘the random walk technique’ of civilians in Kosovo who had been exposed to traumatic events during the war of 1998/1999	N/A	N/A	SIDES	1	127	102 (81%)	18–62	39.20%	1	6 years	The Harvard Trauma Question naire – part I plus 17 different mostly war-related traumatic events	Not stated	N/A	2/127 (however each of the subsets of DESNOS symptoms were present to a clinically significant degree in sub-groups of this sample – presented in table)
Evans (2012)	A sample of 37 adult refugees who had been resettled in Australia, selected using direct recruitment (asking refugee community leaders and refugee specialist services such as migrant centre to disseminate information inviting participation) and snowball sampling techniques	Constructed an assessment tool based on symptoms of AO-CPTSD as defined in the literature by Ebert & Dyck, 2004.	1	Constructed an assessment tool based on SIDES (DESNOS)and based on CIDI (EPCACE)	1	37	36	24–72	29.70%	6	Between 6 months and 30 years.	Not stated.	2–15	CPTSD (current) 13.5%, CPTSD (lifetime) 13.5%	DESNOS (current) 3%, DESNOS (lifetime) 3%; EPCACE 8%
Teodorescu et al. (2012)	A convenience sample of refugees from various backgrounds, now permanent residents in Norway, who were current psychiatric outpatients, referred by treating clinician	N/A	N/A	SIDES	1	61	61 (100%)	18–60	41%	1	Since resettlement: 2% <5y, 14% 6–10y, 84% >10y; Since worst traumatic event: M mean 17.8 years, SD 10.2; F mean 16.5 years, SD 8.8	Life Events Checklist (LEC)	F 2–15, M 5–15	N/A	16% current, 82% lifetime
Kissane et al. (2014)	A convenience sample of asylum seekers undergoing psychotherapy through a London-based charity the Helen Bamber Foundation, clinicians invited current patients to take part in the study	SIDES. Definition based on complex PTSD defined in DSM-IV PTSD field trials.	1	N/A	N/A	48	29 (30%)	IQR: 27.5–37; median 32	72.40%	7	Median 5 years, IQR 3–8.5	Three groups: human trafficking, torture and domestic violence	31% torture, 27.6% human trafficking, 13.8% domestic violence	27.60%	N/A
Kyung (2014)	A sample of 531 North Korean defectors residing in a South Korean resettlement institution	Quimette, Saxe, and van der Kolk’s Complex PTSD Interview revised into a questionnaire form by JM Lee	3	N/A	N/A	531	531	Mean 34.6, SD = 9.23	68%	4	Not stated	11-item trauma checklist plus 3 additional items most frequently experienced by North Korean defectors, from the trauma scale of North Korean defectors developed by SR Kang	Most common n = 192 experienced witnessing the death of other	n = 49 CPTSD (11.3%); additional n = 113 CPTSD+PTSD (26.2%)	N/A
Palic & Elklit (2014)	A convenience sample of Bosnian refugees who had permanent residence in Denmark, attending any of six (out of ten) Danish rehabilitation centres for traumatised refugees	N/A	N/A	SIDES-SR	2 “self report questionnaire developed on the basis of the SIDES interview	116	(80%)	30–67	53%	1	16 years	War trauma, unclear how measured; ACE measured using 5 dichotomous questions derived from a previous ACE study, if occurred at 14 years or younger, considered ACE	29% ACE; severe war trauma: 90% loss of family member; 72% torture; 53% beating; 51% imprisonment in detention camps; 33% rape and other sexual assault	N/A	34%
Dokkedah et al. (2015)	The lack of a national register in Uganda made random sampling difficult, the sample of survivors of the war were selected using ‘principles of random sampling’ by local leaders of the four parishes in Awach	ICD-11 Trauma Questionnaire	3	N/A	N/A	314	(100%)	18–25	51%	1	7 years	UNICEF War Trauma Screening Scale adapted for West Africa	Not stated	14.90%	N/A
Tay et al. (2015)	A targeted sample of West Papuan refugees participating in a community survey involving door-to-door inquiries, conducted across six settlements in Port Moresby, Papua New Guinea	Culturally adapted measure (dichotomous for each symptom) using symptomatology of PTSD and CPTSD, which was then applied to the various DSM and ICD definitions	1	N/A	N/A	250	230 (92%)	Mean 37, SD 9.8	40.40%	3	15 years	Exposure to conflict-related traumatic events using an inventory of 22 items (dichotomous) compiled and adapted to the historical context and experiences of West Papuan refugees in PNG	56% exposed to at least one traumatic event	3%	N/A
Nickerson et al. (2016)	A convenience sample of refugees and asylum seekers from a variety of countries of origin who were receiving psychological treatment for trauma-related mental health problems at an outpatient unit for victims of torture and war in either Zurich or Bern, Switzerland	Using six items derived from scales implemented in this study	2	N/A	N/A	152	134 (88.2%)	Mean 42.4 years, SD 9.8	21.60%	8	Mean 9.01 years, SD 6.67	23-item instrument developed for the current study – compilation of trauma events lists from two standardised questionnaires, the HTQ and the PDS	1564	32.80%	N/A
Al Ibraheem et al. (2017)	Two populations: One group of Syrian refugees in the Netherlands, selected by snowballing or chain referral sampling techniques; the other a sample of IDPs in Syria	Cumulative Trauma Disorders Measure (CTD)	2	N/A	N/A	306	306 (5% Syrian data lost due to airstrikes)	18–78	32.70%	Syria 2, Netherlands ?4	Ongoing	Syrian Oppressive Experience (SOE) Scale of 32 items	Not stated	39.50%	N/A
Kira et al. (2017)	A sample of Syrians who identified themselves as refugees, living in Egypt, sampled using snowball or chain referral techniques	Post-cumulative trauma-related disorders measure (P-CTD)	2	N/A	N/A	196	(100%)	18–63	31.60%	Not stated	Not stated	The cumulative stressors and traumas scale short form (CTS-S): 32-item instrument	Mean of cumulative trauma occurrence (the number of types of trauma they suffered) 6.58, SD 4.82	47.40%	N/A
Hecker et al. (2018)	Participants were approached in counselling and information centres for refugees as well as in language and integration courses, in three different parts of Switzerland. 98 refugees mostly from Syria, Afghanistan and Eritrea were included.	ITQ	3	N/A	N/A	98	94/98 (96%)	18–61	14.90%	Refugee (25.5%), Provisional permit (5.3%), Asylum seeker (64.9%), No official status/illegal (2.1%)	Not stated		Not stated	21.30%	N/A
Hyland et al. (2018)	110 treatment-seeking Syrian refugees living in Lebanon. Participants were recruited through International Medical Corps’ (IMC) Lebanon Mental Health programme. IMC case managers identified participants, informed them of the study and gave them the option of participation, before referring them to one of eight IMC psychotherapists.	ITQ	3	N/A	N/A	110	100%	Mean 33.02	80.20%	Most participants were registered with the office of United Nations High Commissioner for Refugees (90.1%, n = 100). A small proportion of the sample resided within a refugee camp (12.7%, n = 14), with the majority living with family members or friends (96.4%, n = 107).	had spent an average of 37.45 months (S.D. = 14.62) in Lebanon		Not stated	36.10%	N/A
Silove et al. (2018)	A PNG government census of all West Papuans residing in the country had been completed the year prior to our study.	R-MHAP	1	N/A	N/A	487	86%	Mean 35.8	44.10%	Refugee (62.6%), permissive residency status (22.8%), citizen of PNG (14.6%).	Not stated		Not stated	9.30%	N/A
Hoffman et al. (2018)	108 Resettled female Yazidi captives sampled from four post-ISIS camps in Northern Iraq/Kurdistan region.	ICD-11 CPTSD questionnaire	3	N/A	N/A	108	100%	Mean 24.42	100%	resettled	1 to 4 months after liberation from ISIS		Not stated	50.90%	N/A
Frost et al. (2019)	428 individuals who endorsed refugee status taken from a nation-wide survey in the US.	Data drawn from the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC II)	2	N/A	N/A	308	308 (120 excluded due to missing data across PTSD items)	Mean 50.94	48.70%	All refugee	Not stated		Not stated	4.90%	N/A

^aType of measure: (Chodoff, 1968) Structured diagnostic/clinical interview; (Herman, 1992) Self report symptom checklist; (Roth et al., 1997) Standardised questionnaire.

^bLiving status: (1) residents; (2) IDP; (3) refugee camp; (4) first asylum; (5) mixed post-conflict; (6) Permanent resettle; (7) asylum seeker; (8) mixed resident status.

Table A4. Results of critical appraisal of studies meeting inclusion criteria showing decision to include or exclude from narrative synthesis

Study	Was the sample frame appropriate to address the target population?	Were study participants sampled in an appropriate way?	Was the sample size adequate?	Were the study subjects and the setting described in detail?	Was the data analysis conducted with sufficient coverage of the identified sample?	Were valid methods used for the identification of the condition?	Was the condition measured in a standard, reliable way for all participants?	Was there appropriate statistical analysis?	Was the response rate adequate, and if not, was the low response rate managed appropriately?	Overall Score out of 9	Overall Appraisal (Include/Exclude)
Weine et al. (1998)	U	U	N	N	N	U	Y	N	N	1	Exclude
Al-Rasheed (2004)	Y	Y	Y	Y	U	N	Y	Y	Y	7	Include
De Jong et al. (2005)	Y	Y	Y	Y	U	N	U	Y	Y	6	Include
Morina and Ford (2008)	U	Y	N	Y	N	N	U	Y	Y	4	Exclude
Evans (2012)	N	N	N	Y	Y	N	N	Y	Y	4	Exclude
Teodorescu et al. (2012)	N	N	Y	Y	Y	N	Y	Y	Y	6	Include
Kissane et al. (2014)	Y	N	N	Y	N	N	Y	Y	N	4	Exclude
Kyung (2014)	N	U	Y	N	Y	N	U	Y	Y	4	Exclude
Palic and Elklit (2014)	Y	N	N	Y	N	N	Y	Y	U	4	Exclude
Dokkedah et al. (2015)	N	N	U	Y	Y	N	Y	Y	Y	5	Include
Tay et al. (2015)	U	Y	Y	Y	U	Y	Y	Y	Y	7	Include
Nickerson et al. (2016)	N	N	Y	N	Y	N	Y	Y	Y	5	Include
Al Ibraheem et al. (2017)	Y	N	U	Y	Y	Y	Y	Y	Y	7	Include
Kira et al. (2017)	Y	N	U	Y	Y	Y	Y	Y	Y	7	Include
Hecker et al. (2018)	Y	N	U	Y	Y	Y	Y	Y	Y	7	Include
Hyland et al.(2018)	Y	N	U	Y	Y	Y	Y	Y	Y	7	Include
Silove et al. (2018)	Y	Y	Y	Y	Y	Y	Y	Y	Y	9	Include
Hoffman et al.(2018)	N	N	U	N	Y	Y	Y	Y	Y	5	Include
Frost et al. (2019)	Y	Y	Y	Y	Y	N	N	Y	Y	7	Include

Y = yes; N = no; U = unclear.

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Data availability statement

The data and materials that support the results or analyses are presented and fully available in our paper.