Assessing complex PTSD and PTSD: validation of the German version of the International Trauma Interview (ITI)

Figures & data

Table 1. Demographics.

	Total sample (n = 243)		Inpatient ward Switzerland (n = 77)		German military (n = 100)		Treatment centres Germany (n = 66)
	Mean/n	SD, range/%	Mean/n	SD, range/%	Mean/n	SD, range/%	Mean/n	SD, range/%
Age, mean (SD), range	40.31	11.27 18–65	41.14	13.09 20–65	40.85	7.96 22–59	38.42	13.13 18–61
Gender, n (%)
Male	130	53.5%	25	32.5%	87	87%	18	27.3%
Female	106	43.6%	52	67.5%	10	10%	44	66.6%
Other/missing	7	2.9%	0	0%	3	3%	4	6.1%
Education level, n (%)
Elementary school	4	1.6%	2	2.6%	1	1%	1	1.6%
Secondary school	34	14%	5	6.5%	18	18%	11	16.7%
Professional training	116	47.7%	43	55.8%	53	53%	20	30.3%
Professional training with college degree	32	13.2%	12	15.6%	11	11%	9	13.6%
Higher education/ university	49	20.2%	15	19.5%	13	13%	21	31.8%
Missing	8	3.3%	0	0%	4	4%	4	6.1%
Civil status, n (%)
In relationship/married	104	42.8	22	28.6%	58	58%	24	36.4%
Single	91	37.5	41	53.2%	21	21%	29	43.9%
Separated/divorced	40	16.5	14	18.2%	18	18%	8	12.1%
Widowed	1	0.4	0	0%	0	0%	1	1.5%
Missing	7	2.8	0	0%	3	3%	4	6.1%
Working situation, n (%)
Full-time working	95	39.1	8	10.4%	87	87%	NA	NA
Part-time working	5	2.1	2	2.6%	3	3%	NA	NA
Not working	72	29.6	67	87%	5	5%	NA	NA
Missing	71	29.2	0	0%	5	5%	NA	NA

Table 2. Overall trauma exposure.

	Experienced^a (%)		Learned about it (%)		Not experienced (%)
	Civilian	Military	Civilian	Military	Civilian	Military
1. Natural disaster	14.0	50.0	3.5	6.0	76.9	38.0
2. Fire or explosion	16.1	74.0	8.4	6.0	64.3	15.0
3. Transportation accident	40.6	70.0	7.7	5.0	46.2	19.0
4. Serious accident	27.3	53.0	4.2	9.0	62.9	33.0
5. Exposure to toxic substance	6.3	26.0	0	3.0	88.1	66.0
6. Physical assault	71.3	57.0	4.9	8.0	18.2	31.0
7. Assault with a weapon	41.3	68.0	9.1	3.0	44.1	22.0
8. Sexual assault	62.9	17.0	1.4	7.0	30.1	71.0
9. Other unwanted or uncomfortable sexual experience	52.4	11.0	0.7	5.0	41.3	79.0
10. Combat/exposure to a war zone	9.1	87.0	3.5	0	81.1	9.0
11. Captivity	15.4	11.0	4.2	7.0	74.8	77.0
12. Life-threatening illness or injury	27.3	49.0	2.8	5.0	64.3	41.0
13. Severe human suffering	43.4	75.0	4.2	3.0	46.9	19.0
14. Sudden violent death	16.1	51.0	19.6	19.0	58.7	26.0
15. Sudden accidental death	9.8	39.0	7.7	22.0	76.9	35.0
16. Serious injury, harm, or death caused to someone else	9.1	37.0	0.7	0	84.6	59.0
17. Other	42.7	54.0	1.4	2.0	50.3	35.0

Note: ^aexperienced, witnessed, or job-related exposure. Civilian n = 143, military n = 100.

Figure 1. Alternative tested models of the latent structure of ICD-11 PTSD and CPTSD symptoms.

Note: PTSD = Posttraumatic Stress Disorder, DSO = Disturbances in Self-Organization, CPTSD = Complex Posttraumatic Stress Disorder, Re = Re-experiencing, Av = Avoidance, Th = Sense of current threat, AD = Affect dysregulation, NSC = Negative-self-concept, DR = Disturbed relationships.

Table 3. Endorsement of ITI symptoms and diagnostic rates.

	Civilian n = 143		Military n = 100
	n	%	n	%
ITI Clusters
Re-experiencing	134	93.7	67	67
Avoidance	138	96.5	73	73
Sense of threat	130	90.9	71	71
Affect dysregulation	127	88.8	73	73
Negative self-concept	101	70.6	38	38
Disturbed relationships	102	71.3	59	59
ITI Diagnoses
PTSD endorsed (DSO excluded)	43	30	33	33
CPTSD endorsed (PTSD+DSO)	76	53.1	21	21
DSO only	10	6.9	10	10
No diagnosis	14	9.8	36	36

Note: ITI = International Trauma Interview; PTSD = ITI Posttraumatic Stress Disorder, DSO = ITI Disturbances in Self-Organization.

Table 4. Model fit statistics for the alternative models of the International Trauma Interview.

Model	χ^2(df)	p	CFI	TLI	RMSEA	90% CI RMSEA	SRMR
Civilian
1. Unidimensional	321.45(77)	<.001	0.675	0.616	0.152	0.135–0.169	0.108
2. Six factors correlated	221.69(64)	<.001	0.910	0.850	0.110	0.077–0.151	0.050
3. Two factors second-order	257.19(72)	<.001	0.754	0.689	0.137	0.119–0.153	0.170
Military
4. Unidimensional	215.33(54)	<.001	0.633	0.551	0.176	0.152–0.201	0.126
5. Six factors correlated	42.59(39)	.319	0.992	0.986	0.031	0.000–0.079	0.051
6. Two factors second-order	53.56(47)	.237	0.985	0.979	0.038	0.000–0.080	0.062

Note: χ², Chi-Square Goodness of Fit statistics; df, degrees of freedom; p = Statistical significance; CFI, Comparative Fit Index; TLI, Tucker Lewis Index; RMSEA (90% CI), Root Mean Square Error of Approximation with 90% confidence intervals; SRMR, standardised root-mean-square residual; Best fitting model in bold; n = 143 civilians, n = 100 military personnel.

Table 5. Partial correlation coefficients between ITI subscales and PCL subscales, BDI and BSI, controlling for age and gender: Civilian (above diagonal) and military participants (below diagonal).

	ITI PTSD	ITI DSO	PCL total	PCL Int	PCL Av	PCL CM	PCL Ar	BDI	BSL	BSI IS	BSI Anx	BSI Agg	BSI Pho	BSI Par	BSI Psy
ITI PTSD	1	.52***	.47***	.58***	.26*	.39**	.45***	.23	.16	.20	.24*	.23	.12	.23*	.20
ITI DSO	.49***	1	.22*	.22	.20	.28*	.23*	.38***	.12	.39**	.22	.26*	.16	.28**	.34**
PCL total	.72***	.57**	1	.85***	.72***	.81***	.81***	.28*	.37**	.23*	.27*	.24*	.17	.17	.20
PCL Int	.72***	.39***	.88***	1	.49***	.64***	.67***	.23	.35**	.11	.17	.12	.09	.05	.07
PCL Av	.68**	.33**	.71***	.67***	1	.42***	.35**	.22	.19	.34**	.35**	.28*	.29*	.22	.26*
PCL CM	.60***	.68***	.91***	.67*	.50***	1	.51***	.32**	.31**	.20	.16	.15	.10	.16	.18
PCL Ar	.66***	.52***	.91***	.72*	.53***	.77***	1	.28*	.25*	.15	.18	.28*	.16	.17	.18
BDI	.56***	.74***	.76***	.59***	.44***	.82***	.67***	1	.34**	.48***	.41***	.32**	.30*	.48***	.54***
BSL	–	–	–	–	–	–	–	–	1	.05	.09	.09	.05	−.00	.12
BSI IS	.50***	.74***	.64***	.47***	.35***	.73***	.53***	.83***	–	1	.71***	.65***	.61***	.72***	.79***
BSI Anx	.72***	.51***	.75***	.78***	.56***	.74***	.72***	.75***	–	.66***	1	.73***	.80***	.65***	.74***
BSI Agg	.44***	.60***	.64***	.44***	.35***	.62***	.73****	.67***	–	.75***	.61***	1	.57***	.69***	.74***
BSI Pho	.73***	.42***	.74***	.66***	.53***	.61***	.63***	.63***	–	.82***	.81***	.53***	1	.58***	.64***
BSI Par	.42***	.59***	.50***	.32**	.18	.61***	.43***	.68***	–	.79***	.50***	.64***	.39***	1	.86***
BSI Psy	.52***	.63***	.63***	.48***	.37***	68***	50***	.72***	–	.83***	.75***	.67***	.63***	.68*	1

Note: ITI = International Trauma Interview, ITI PTSD = ITI Posttraumatic Stress Disorder, ITI DSO = ITI Disturbances in Self-Organization, PCL = PTSD Check List–5, PCL total = PCL toatl score, PCL Int = PCL-5 intrusions, PCL Av = PCL-5 avoidance, PCL CM = PCL-5 cognitions and mood, PCL Ar = PCL-5 arousal; BDI = Beck Depression Inventory II; BSL = Borderline Symptom List; BSI = Brief Symptom Inventory-53, BSI IS = BSI-53 interpersonal sensitivity, BSI Anx = BSI-53 anxiety, BSI Agg = BSI-53 aggression, BSI Pho = BSI-53 phobic anxiety, BSI Par = BSI-53 paranoid ideation, BSI Psy = BSI-53 psychoticism. * p < .05, ** p < .01, *** p < .001.

Data availability statement

The data that support the findings of this study are available upon reasonable request. Access to the German Military subsample must be requested from the German Ministry of Defense ([email protected]) while the data collected in civil in- and outpatient centres in Germany and Switzerland are available from the corresponding author.