Page 37 - Post-traumatic stress disorder in adults with mild intellectual disability: Screening, assessment, and brief intensive EMDR therapy

Reliability and validity of DITS-ID
a proxy questionnaire, whereas feelings of anxiety and depression due to
their private nature may be missed by others. Second, behavioral problems
were not assessed, while PTSD symptoms and behavioral problems are
interrelated (Kildahl & Helverschou, 2023; Kildahl et al., 2020; Mason-
Roberts et al., 2018; McNally et al., 2021; Rittmannsberger et al., 2020).
The purpose of the present study was to assess the interrater reliability and
construct validity of the DITS-ID-adults in adults with MID-BIF. This study
replicated and extended the study by Mevissen et al. (2020) by examining
the construct validity of the DITS-ID-adults. We used the self-reported
Brief Symptom Inventory-18 (BSI-18) to measure symptoms of anxiety
and depression, and the Behavior Problems Inventory (BPI) to measure
behavioral problems. In addition, we used the IES-ID and ADESS, which
were also used in Mevissen et al. (2020) study. We hypothesized that there
would be positive associations between the number of symptoms on the
DITS-ID-adult and the presence or absence of a PTSD classification on one
hand, and questionnaire scores on the other (i.e., ADESS, BSI-18, BPI, and
IES-ID). In addition, we examined the association between reporting an
event that met Criterion A for PTSD and meeting the PTSD symptom criteria
(both measured with the DITS-ID-adults). We hypothesized that reporting a
Criterion A event would be associated with meeting PTSD symptom criteria
and that individuals meeting PTSD symptom criteria would report more
Criterion A events than those not meeting PTSD symptom criteria.
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Materials and methods
Participants and Setting
Individuals with a mild intellectual disability or borderline intellectual
functioning (MID-BIF) who were all living in supported housing off two ID
care services in the Netherlands (i.e., ‘s Heeren Loo and Trajectum) were
informed about the aims of the study by their psychologist. Participation
was voluntary and individuals interested in participating received an
information letter. The inclusion criteria were that the participants were at
least 18 years old, had a diagnosis of MID or BIF, and had sufficient Dutch
language skills. Suicidality, drug use, and serious sedating medications
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