Trauma, intellectual and/or developmental disability, and multiple, complex needs: A scoping review of the literature.
The trauma-IDD evidence base is thin—write your own trauma-informed playbook.
01Research in Context
What this study did
Cook et al. (2021) searched every paper on trauma in people with intellectual or developmental disabilities.
They also looked for studies on clients who have many needs at once.
The team mapped what has and has not been studied.
What they found
Only a handful of papers exist. Most test one-to-one therapy.
Almost none tell agencies how to build a trauma-informed system.
The authors call the evidence “sparse and fragmented.”
How this fits with other research
Khokhar et al. (2025) show that mixing several ABA protocols helps adults with ID and problem behavior. Shelley et al. agree that single-shot treatments are the norm, but they warn that trauma is rarely on the radar.
Lotfizadeh et al. (2020) found that PTSD signs, not trauma history itself, predict caregiver-rated challenging behavior. Shelley’s review says PTSD is barely studied; the 2020 paper gives you a reason to screen for it anyway.
Samtani et al. (2021) scouted cancer care for people with ID and also found “sparse” literature. Both reviews echo the same gap: clinicians lack guidance for complex, life-altering conditions.
Why it matters
If your caseload includes multiply complex clients, expect no ready-made manual. Use what exists—like PTSD screens from Lotfizadeh et al. (2020) and multi-protocol packages from Khokhar et al. (2025)—and build your own trauma-informed policies. Start small: add a trauma checklist to intake and train staff to watch for triggers during routine ABA sessions.
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02At a glance
03Original abstract
BACKGROUND: Trauma is a significant underlying factor in the multimorbidity of people with Intellectual and/or Development Disabilities (IDD). This relationship is further complicated by a growing recognition of a subset of multiply stigmatized individuals with an IDD and complex, intersecting health and social needs. AIM: The aim of this review was to examine what is known about trauma and people with an IDD and complex needs, as defined by Community Living British Columbia's (CLBC) Multiple, Complex Needs (MCN) framework, through a broad review of relevant literature. METHOD AND PROCEDURES: We conducted a scoping review of the peer-reviewed (9 disability journals; 7 academic databases) and grey (2 grey literature databases) on IDD and trauma through an inclusive approach that used search criteria drawn from the defining features of CLBC's MCN Framework. OUTCOMES AND RESULTS: Apart from there being a limited amount of research on trauma and IDD, two key findings emerged. Through differing approaches that get at issues of trauma in different ways (i.e., through adverse life events or experiences of abuse), the first finding is that the research related to trauma and IDD is not cleanly linked together. The second is the focus on treatment services or interventions and not on what's happening at the organizational or system level. CONCLUSION AND IMPLICATIONS: There is limited research on trauma and IDD making it even more important to unify the evidence that exists. However, the literature is not integrated across different theoretical and disciplinary perspectives. In addition, the focus of trauma-related research that is occurring is interventions at the individual versus system level. Also needed are studies that explore trauma-informed practice from an organizational or top-down perspective.
Research in developmental disabilities, 2021 · doi:10.1016/j.ridd.2021.103939