Page 35 - Post-traumatic stress disorder in adults with mild intellectual disability: Screening, assessment, and brief intensive EMDR therapy

Reliability and validity of DITS-ID
Introduction
According to the DSM-5-TR, PTSD is characterized by symptoms of
intrusions, avoidance, negative alterations in cognition and mood, and
alterations in arousal and reactivity following exposure to a potentially
traumatic event. Such an event is defined under the A criterion when an
individual has directly experienced, witnessed or learned that a friend or
relative has been exposed to actual or threatened death, serious injury, or
sexual violence. PTSD symptoms last for at least one month and cause
distress in social or occupational functioning or functioning in other important
areas (American Psychiatric Association [APA], 2022). Individuals with mild
intellectual disability or borderline intellectual functioning (MID-BIF; IQ 50–
85) may be at a relatively higher risk of developing post-traumatic stress
disorder (PTSD) than people without an intellectual disability (ID; de Vogel
& Didden, 2022; Mason-Roberts et al., 2018; Mevissen & de Jongh, 2010;
Mevissen et al., 2016; Nieuwenhuis et al., 2019). While PTSD symptoms
are associated with a range of impairments and mental health conditions,
studies have found long delays from onset to treatment if diagnosis and
treatment are sought (Goldstein et al., 2016; Pietrzak et al., 2012).
PTSD frequently remains unnoticed in individuals with MID-BIF (Nieuwenhuis
et al., 2019), although PTSD symptoms manifest similarly in persons
with MID-BIF as in people without ID (Hoogstad et al., 2023; Mevissen et
al., 2016, 2020). In a cross-sectional study involving 570 severely mentally
ill participants to explore the presence of MID-BIF based on a screener
and PTSD, among the group with MID-BIF, there were much higher rates of
suspected PTSD (48%) than the number of PTSD diagnoses (8%) already
known in this sample before participating in the study (Nieuwenhuis et
al., 2019). A possible explanation for the difficulty in recognizing PTSD
in individuals with MID-BIF is that PTSD symptoms are attributed to the
characteristics of MID-BIF or another mental disorder, a phenomenon
called diagnostic overshadowing (Jopp & Keys, 2001). PTSD symptoms
show overlap with symptoms of anxiety and depressive disorders (Kildahl
& Helverschou, 2023; Kildahl et al., 2020a, 2020b), problems that occur at
least as often among people with an intellectual disability as in the general
population and for which recognition has been increasing (Emerson et
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