Validation of the International Trauma Interview (ITI) for the Clinical Assessment of ICD-11 Posttraumatic Stress Disorder (PTSD) and Complex PTSD (CPTSD) in a Lithuanian Sample

Figures & data

Figure 1. Alternative model solutions 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 1. Descriptive statistics of the study variables

	Total sample (N = 103)	No diagnosis (n = 62)	PTSD (n = 19)	CPTSD (n = 22)
	Mean (SD)	Mean (SD)	Mean (SD)	Mean (SD)
ITI total	13.22 (8.57)	8.02 (5.39)	16.89 (3.83)	24.73 (5.36)
PTSD	6.53 (4.47)	3.61 (2.63)	10.68 (1.83)	11.18 (3.26)
DSO	6.69 (5.25)	4.40 (4.28)	6.21 (2.86)	13.55 (2.96)
Re-experiencing	1.75 (1.64)	0.66 (0.79)	3.37 (1.01)	3.41 (1.26)
Avoidance	2.61 (1.86)	1.68 (1.62)	3. 95 (1.08)	4.09 (1.31)
Sense of threat	2.17 (1.78)	1.27 (1.43)	3.37 (1.21)	3.68 (1.46)
Affect dysregulation	2.06 (1.41)	1.45 (1.18)	2.47 (1.07)	3.41 (1.18)
Negative self-concept	2.27 (2.19)	1.45 (1.80)	1.89 (1.49)	4.91 (1.60)
Disturbed relationships	2.36 (2.58)	1.50 (2.27)	1.84 (2.09)	5.23 (1.60)
ITQ total	25.63 (10.70)	20.16 (8.60)	32.11 (8.43)	35.45 (7.28)
PTSD	12.63 (6.16)	10.02 (5.27)	16.32 (4.76)	16.82 (5.76)
DSO	13.00 (5.87)	10.15 (4.89)	15.79 (4.78)	18.64 (3.72)
PHQ-9	13.41 (6.73)	10.29 (5.46)	17.11 (5.79)	19.00 (5.51)
GAD-7	11.15 (5.32)	8.79 (4.43)	13.95 (4.34)	15.36 (4.71)
DERS	102.50 (24.60)	92.73 (22.31)	112.68 (20.47)	121.27 (19.72)
DSS	13.50 (13.02)	7.18 (6.40)	19.21 (12.12)	26.41 (16.02)
BPS	34.64 (8.20)	32.08 (7.56)	36.74 (7.36)	40.05 (7.79)
RSES	24.83 (5.91)	26.94 (5.38)	22.74 (5.79)	20.73 (4.71)
ECR-S Anxiety	27.97 (8.70)	27.87 (8.40)	26.37 (9.71)	29.64 (8.76)
ECR-S Avoidance	20.36 (7.16)	19.11 (6.92)	19.63 (6.59)	24.50 (7.04)
WHO-5	33.71 (15.55)	39.10 (14.16)	28.84 (14.02)	22.73 (13.77)

PTSD = Posttraumatic Stress Disorder, CPTSD = Complex Posttraumatic Stress Disorder, DSO = Disturbances in Self-Organization, ITI = International Trauma Interview, ITQ = International Trauma Questionnaire, PHQ-9 = Patient Health Questionnaire-9, GAD-7 = Generalized Anxiety Disorder-7, DERS = Difficulties in Emotion Regulation Scale, DSS = Dissociative Symptoms Scale, BPS = Borderline Pattern Scale, RSES = Rosenberg Self-esteem Scale, ECR-S = Experience in Close Relationships Scale – Short Form, WHO-5 = WHO-5 Well-being Index.

Table 2. Model fit statistics for the tested models of the International Trauma Interview (N = 103)

Model	χ^2 (df)	p	CFI	TLI	RMSEA (90% CI)
1	224.49 (54)	<.001	.909	.889	.175 (.152 – .199)
2	33.78 (39)	.706	1.000	1.005	.000 (.000 – .054)
3	47.79 (47)	.441	1.000	.999	.013 (.000 – .066)

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. Best fitting model is in bold.

Table 3. Standardized regression coefficients between PTSD and DSO, and other measured variables

	ITQ PTSD	ITQ DSO	PHQ-9	GAD-7	DERS	DSS	BPS	RSES	ECR-S Anx.	ECR-S Avoid.	WHO-5
ITI PTSD	.91***	.23*	.30**	.48***	.25	0.70***	.28*	−.20	−.29*	.02	−.14
ITI DSO	−.23	.57***	.48***	.19	.39**	0.05	.36**	−.36**	.42**	.37**	−.53***
Age	.16	−.04	.00	−.07	−.08	−.04	−.08	0.26**	−.27*	.13	.00
Gender	−.13	.01	−.07	.00	.07	−.05	.04	0.07	.04	−.10	.05
R^2	.54***	.56***	.51***	.41***	.38***	.54***	.37***	.36***	.13	.16**	.40***

These are the results of the SEM model exploring associations between the ITI latent factors and other mental health indicators included in the model as observed variables. The associations in the model were adjusted for age and gender.

ITI = International Trauma Interview, PTSD = Posttraumatic Stress Disorder, DSO = Disturbances in Self-Organization, ITQ = International Trauma Questionnaire, PHQ-9 = Patient Health Questionnaire-9, GAD-7 = Generalized Anxiety Disorder-7, DERS = Difficulties in Emotion Regulation Scale, DSS = Dissociative Symptoms Scale, BPS = Borderline Pattern Scale, RSES = Rosenberg Self-esteem Scale, ECR-S = Experience in Close Relationships Scale – Short Form, Anx. = Anxiety, Avoid. = Avoidance, WHO-5 = WHO-5 Well-being Index.

* p < .05, ** p < .01, *** p < .001.

Table 4. Agreement and consistency between the ITI and the ITQ

Symptom cluster	ITI % endorsing	ITQ % endorsing	κ (95% CI)	p	ITI Mean (SD)	ITQ Mean (SD)	ICC (95% CI)
Re-experiencing	47.6%	61.2%	.50 (.34, .66)	<.001	1.75 (1.64)	3.17 (2.50)	.59 (.45, .70)
Avoidance	63.1%	75.7%	.35 (.16, .54)	<.001	2.61 (1.86)	4.37 (2.67)	.44 (.27, .58)
Sense of threat	58.3%	91.3%	.10 (−.03, .23)	.113	2.17 (1.78)	5.10 (2.13)	.38 (.20, .53)
Affect dysregulation	58.3%	93.2%	.19 (.06, .31)	.001	2.06 (1.41)	4.10 (1.85)	.54 (.38, .66)
Hyperactivation	52.4%	90.3%	.17 (.05, .29)	.005	1.49 (0.97)	2.69 (0.97)	.45 (.29, 60)
Hypoactivation	17.5%	45.6%	.32 (.17, .47)	<.001	0.57 (0.85)	1.41 (1.41)	.46 (.29, .60)
Negative self-concept	36.9%	68.0%	.29 (.15, .44)	<.001	2.27 (2.19)	4.37 (2.62)	.56 (.41, .68)
Disturbed relationships	41.7%	76.7%	.29 (.15, .42)	<.001	2.36 (2.58)	4.53 (2.52)	.58 (.44, .70)
PTSD (CPTSD cases included)	39.8%	49.5%	.49 (.33, .66)	<.001	6.53 (4.47)	12.63 (6.16)	.60 (.46, .71)
PTSD (CPTSD cases excluded)	18.4%	10.7%	−.08 (−.22, .06)	.397	-	-	-
DSO	28.2%	54.4%	.38 (.23, .53)	<.001	6.69 (5.25)	13.00 (5.87)	.66 (.54, .76)
CPTSD	21.4%	38.8%	.33 (.15, .51)	<.001	13.22 (8.57)	25.63 (10.70)	.69 (.58, .78)

ITI = International Trauma Interview, ITQ = International Trauma Questionnaire, PTSD = Posttraumatic Stress Disorder, CPTSD = Complex Posttraumatic Stress Disorder, DSO = Disturbances in Self-Organization, ICC = Intraclass correlation coefficient.