Page 56 - Post-traumatic stress disorder in adults with mild intellectual disability: Screening, assessment, and brief intensive EMDR therapy

Chapter 3
Abstract
Background: This study aimed to evaluate the validity and reliability of the
adult self-report and proxy version of the Trauma Screener-Intellectual
Disability (TS-ID) in adults with mild intellectual disability or borderline
intellectual functioning (MID-BIF). An optimal cut-off value was determined
for the ratio of specificity to sensitivity for predicting the diagnosis of post-
traumatic stress disorder (PTSD).
Methods: The TS-ID was adapted from a Dutch Child and Adolescent
Trauma Screener, for use with adults with MID-BIF. Outcomes based on
the TS-ID were compared with the presence of PTSD, as classified using
the Diagnostic Interview Trauma and Stressors–Intellectual Disability
(Mevissen et al., 2018). The TS-ID adult version was administered to 97
participants with MID-BIF who lived in supported housing, whereas the TS-
ID proxy version was administered to 92 family members or professional
caregivers.
Results: The TS-ID adult version showed high internal consistency
(Cronbach’s α = .94) and excellent validity (AUC = .94) for distinguishing
PTSD in adults with MID-BIF. Optimal specificity and sensitivity was found
at a cut-off score of 18. Although the TS-ID proxy version demonstrated
excellent internal consistency (Cronbach’s α = .93), it showed no validity in
statistically distinguishing PTSD in adults with MID-BIF.
Conclusions: The TS-ID showed favourable psychometric qualities as a
screening instrument of PTSD in the case for people with MID-BIF.
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