Page 44 - Post-traumatic stress disorder in adults with mild intellectual disability: Screening, assessment, and brief intensive EMDR therapy

Chapter 2
Construct Validity
Association Between PTSD Symptom Scores and BSI–18 Scores
Correlations between DITS-ID-adults’ total number of PTSD symptoms
and PTSD classification (“yes” or “no”) and BSI–18 scores total score and
subscales (BSI–18 was completed by the participant), were strong to very
strong (see Table 2).
Table 2. Correlations between DITS-ID-adults total number of PTSD symptoms and PTSD
classification (‘yes’ or ‘no’) and BSI-18 scores (total score and subscales).
BSI–18
(‘yes’ or ‘no’)
PTSD classification
Number of PTSD symptoms
n r p n rpb p
Note. Pearson correlation coefficients (r) and point-biserial correlation coefficients (rpb) are used
for analyses.
Total score 97 .75 <.001 97 .61 <.001
Somatization 97 .64 <.001 97 .46 <.001
Anxiety 97 .70 <.001 97 .62 <.001
Depression 97 .73 <.001 97 .58 <.001
Association Between PTSD Symptom Scores and BPI Scores
No significant correlations were found between the DITS-ID-adults’
total number of PTSD symptoms and BPI frequency scores (BPI was
completed by proxy informants). However, moderate correlations were
found between the number of PTSD symptoms and the BPI total severity
score (n = 91, r = .28, p < .007), BPI self-injurious behavior severity score
(n = 94, r = .23, p < .024) and BPI stereotyped behavior severity score
(n = 93, r = .23, p < .028). No correlations between the PTSD classification
(“yes” or “no”) and the BPI total score or for the subscales of the BPI were
statistically significant (see Table 3).
Association Between PTSD Symptom Scores and IES-ID Scores
A very strong correlation was found between the total score on the IES-ID
completed by the participant and the total number of PTSD symptoms on
the DITS-ID-adults (n = 96, r = .81, p < .001) and the total score on the IES-
ID and the PTSD classification based in the DITS-ID-adults (“yes” or “no”)
(n = 96, r = .65, p < .001).
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