Dissociative symptoms mediate the relation between PTSD symptoms and functional impairment in a sample of military members, veterans, and first responders with PTSD

Figures & data

Table 1. Demographic characteristics of the study sample.

Characteristics	Combined sample, n = 62	Military and veteran, n = 32	First Responder, n = 27
Demographic Characteristics	Mean (SD)
Sex (female:male)	10:52	7:25	2:25
Age	45.9 (9.5)	45.2 (11.1)	47.3 (7.3)
Education	% of Sample
8^th grade or less	1.6	3.1	0
Some high school	4.8	6.3	0
High school	16.1	21.9	11.1
Technical or trade school	12.9	18.9	7.4
Some college or university	25.8	28.1	25.9
Diploma or bachelor’s degree	32.3	12.5	51.9
Graduate degree	6.5	9.4	3.7
Income	% of Sample
Employed	59.7	40.6	77.8
Employment Insurance	8.1	3.1	14.8
Pension	19.4	31.3	3.7
Disability Insurance	25.8	28.1	25.9
Other (e.g. Investment, WSIB, Inheritance)	8.1	9.4	7.4
No Income	3.2	6.3	0

Table 2. Correlations (Pearson’s r) between functional impairment and PTSD and associated symptom dimensions (N = 62 for all variables except for ACE-Q, N = 59).

	WHODAS Total
ACE-Q	0.27
PCL Total	0.30
PCL Intrusions	0.32
PCL Avoidance	0.16
PCL Cognition and Mood	0.23
PCL Arousal and Reactivity	0.30
MDI Total	0.59*
MDI Disengagement	0.57*
MDI Depersonalization	0.47*
MDI Derealization	0.59*
MDI Emotional Constriction	0.52*
MDI Memory Dissociation	0.50*
MDI Identity Dissociation	0.31
DASS-Depression	0.47*
DASS-Anxiety	0.40*
DASS-Stress	0.23
DERS Total	0.50*
TAS Total	0.43*

*Significant after controlling for multiple comparisons, p < .002;

ACE-Q, Adverse Childhood Experiences Questionnaire; PCL, PTSD Checklist For DSM-5; MDI, Multiscale Dissociation Inventory; DASS, Depression Anxiety Stress Scale; DERS, Difficulties in Emotion Regulation Scale; TAS, Toronto Alexithymia Scale.

Table 3. Clinical characteristics of study sample and comparison of clinical measures and exposure to ACEs between military members/veterans and first responders.

	Combined sample, n = 62	Military and veteran, n = 32	First Responder, n = 27	F (1,58)
Clinical Characteristics	Mean (SD)
Functional Disability (WHODAS 2.0)	53.9 (18.2)	62.3 (14.2)	45.8 (18.3)	15.15**
PTSD Symptoms (PCL-5)
Total	59.5 (10.3)	59.8 (10.9)	59.8 (9.8)	0.00
Intrusions	14.5 (4.2)	14.8 (4.6)	14.7 (3.7)	0.00
Avoidance	6.1 (1.8)	6.1 (1.6)	6.3 (2.0)	0.05
Cognition and Mood	21.5 (3.8)	21.4 (4.0)	21.2 (3.5)	0.02
Arousal and Reactivity	17.1 (3.4)	17.5 (3.5)	21.2 (3.5)	0.37
Dissociative Symptoms (MDI)
Total	69.5 (25.4)	75.4 (27.9)	65.1 (21.3)	2.48
Disengagement	16.3 (4.9)	17.0 (4.7)	16.1 (5.2)	0.44
Depersonalization	8.9 (4.9)	10.0 (5.5)	8.1 (4.1)	2.33
Derealization	11.5 (5.2)	12.9 (5.4)	10.2 (4.8)	4.17*
Emotional Constriction	14.0 (6.0)	15.3 (6.1)	13.3 (5.5)	1.64
Memory Dissociation	12.2 (5.6)	13.1 (6.2)	11.6 (4.8)	1.19
Identity Dissociation	6.5 (3.1)	7.0 (3.9)	5.8 (1.7)	2.33
Emotion Dysregulation (DERS)	119.5 (24.3)	123.8 (27.9)	116.9 (22.1)	1.18
Alexithymia (TAS)	63.4 (12.3)	66.3 (13.6)	59.7 (9.9)	4.29*
DASS-Depression	27 (10.4)	29.8 (10.6)	24.4 (9.6)	4.09*
DASS-Anxiety	23.4 (10.1)	25.8 (9.4)	20.6 (10.2)	4.16*
DASS-Stress	27.5 (8.5)	27.8 (7.8)	27.5 (9.5)	0.02
ACE-Q Total	3.36 (2.73)	3.67 (2.70)	3 (2.79)	0.83
ACE-Q (n = 59; n = 30 Military/Veteran; n = 26 First Responder)	% of Sample Endorsing			Χ^2(2)
Emotional Abuse	57.6	60	53.8	0.22
Physical Abuse	50.8	53.3	50	0.06
Sexual Abuse	23.7	33.3	15.4	2.39
Emotional Neglect	38.9	36.7	42.3	0.19
Physical Neglect	18.6	23.3	15.4	0.56
Parental Separation/Divorce	40.7	43.3	34.6	0.44
Domestic Violence	23.7	33.3	11.5	3.71
Substance Abuse	39.0	40	38.5	0.01
Mental Illness	33.9	36.7	30.8	0.22
Incarceration of household member	6.8	6.7	7.7	0.02

*p < .05, ** p < .01.

PCL, PTSD Checklist For DSM-5; MDI, Multiscale Dissociation Inventory; DASS, Depression Anxiety Stress Scale; DERS, Difficulties in Emotion Regulation Scale; TAS, Toronto Alexithymia Scale; ACE-Q, Adverse Childhood Experiences Questionnaire.

F refers to F statistic for univariate analysis of variance; Χ² refers to the chi-square statistic for Pearson’s chi-square test.

Table 4. Correlation matrix for dissociation symptom severity (MDI Total), PTSD symptom severity (PCL Total), and functional disability (WHODAS Total), N = 62 (Pearson’s r reported).

Variable	2	3
1. MDI Total	0.50***	0.59***
2. PCL Total		0.30*
3. WHODAS Total

*p < .05; **p < .01; ***p < .001.

PCL, PTSD Checklist For DSM-5; MDI, Multiscale Dissociation Inventory; WHODAS. World Health Organization Disability Assessment Schedule 2.0.

Table 5. Mediation effects of dissociation symptom severity (MDI Total) on the relationship between PTSD symptom severity (PCL Total) and functional disability (WHODAS Total), N = 62.

Regression Paths	b	SE	p
Mediation a path (PCL Total on MDI Total)	1.22	0.28	< .001
Mediation b path (MDI Total on WHODAS Total)	0.42	0.09	< .001
Total effect, c path (PCL Total on WHODAS Total, No Mediator)	0.54	0.22	< .05
Direct effect c’ (PCL Total on WHODAS Total including MDI Total as mediator)	0.03	0.21	0.902
Indirect effect bootstrapped (c – c’) with bootstrapped 95% CI	0.51 [0.27–0.79]

b = unstandardized coefficient; SE = standard error; CI = confidence interval. Fit for mediation model R² = 0.35, F (2, 59) = 15.83, p < .001.

PCL, PTSD Checklist For DSM-5; MDI, Multiscale Dissociation Inventory; WHODAS, World Health Organization Disability Assessment Schedule 2.0.

Figure 1. Depiction of the mediation model where dissociative symptoms (MDI Total) mediate the relation between PTSD severity and functional impairment. The effect of PCL Total on change in WHODAS Total when MDI Total is introduced as a mediator (c’) is nonsignificant.

b = unstandardized coefficients; a = effect of PCL Total on change in MDI Total; b) effect of MDI Total on change in WHODAS Total; c = the total effect; c’ = the direct effect MDI, multiscale dissociation inventory; PCL-5, PTSD checklist for DSM-5; WHODAS, World Health Organization Disability Assessment Schedule 2.0.

Table 6. Correlation matrix for derealization symptoms (MDI derealization), PTSD symptom severity (PCL Total), and functional disability (WHODAS Total), N = 62 (Spearman’s rho reported).

Variable	2	3
1. MDI Derealization	0.56***	0.59***
2. PCL Total		0.30*
3. WHODAS Total

*p < .05; **p < .01; ***p < .001.

PCL, PTSD Checklist For DSM-5; MDI, Multiscale Dissociation Inventory; WHODAS, World Health Organization Disability Assessment Schedule 2.0.

Table 7. Mediation effects of derealization symptoms (MDI derealization) on the relationship between PTSD symptom severity (PCL Total) and functional disability (WHODAS Total), N = 62.

Regression Paths	b	SE	p
Mediation a path (PCL Total on MDI Derealization)	0.29	0.05	< .001
Mediation b path (MDI Derealization on WHODAS Total)	2.10	0.44	< .001
Total effect, c path (PCL Total on WHODAS Total, No Mediator)	0.54	0.22	< .05
Direct effect c’ (PCL Total on WHODAS Total including MDI Derealization as mediator)	−0.06	0.22	0.785
Indirect effect bootstrapped (c – c’) with bootstrapped 95% CI^b	0.60 [0.33–0.89]

b = unstandardized coefficient; SE = standard error; CI = confidence interval. Fit for mediation model R² = 0.34, F (2, 59) = 15.40, p < .001.

PCL, PTSD Checklist For DSM-5; MDI, Multiscale Dissociation Inventory; WHODAS, World Health Organization Disability Assessment Schedule 2.0.

Figure 2. Depiction of the mediation model where derealization symptoms (MDI derealization) mediate the relation between PTSD severity (PCL Total) and functional impairment (WHODAS Total). The effect of PCL Total on change in WHODAS Total when MDI derealization is introduced as a mediator (c’) is nonsignificant.

b = unstandardized coefficients; a = effect of PCL Total on change in MDI derealization; b) effect of MDI derealization on change in WHODAS Total; c = the total effect; c’ = the direct effect MDI, Multiscale dissociation inventory; PCL-5, PTSD Checklist for DSM-5; WHODAS, World Health Organization Disability Assessment Schedule 2.0.