Impact of additional disabilities on adaptive behavior and support profiles for people with intellectual disabilities.
Extra disabilities forecast bigger skill gaps and higher support needs, not worse behavior.
01Research in Context
What this study did
Wacker et al. (2009) looked at how extra disabilities change the picture for people with intellectual disability.
They counted each added diagnosis and tracked two things: daily living skills and how much help each person needed.
The team also checked if more disabilities meant more problem behavior.
What they found
More diagnoses meant bigger gaps in dressing, cooking, and other life skills.
Support needs rose in step with the number of added disabilities.
Surprise: extra disabilities did not raise challenging behavior scores.
How this fits with other research
Giesbers et al. (2020) extends the same pattern to kids. Each extra developmental disability pushed child behavior problems and parent stress higher.
Dinora et al. (2023) picks up where Julia stops. They show that people who need the most hours often still get the worst life outcomes.
DiStefano et al. (2020) explains why testing is tricky. Standard tools floor-out when severe ID pairs with motor or sensory issues.
Why it matters
When you write a support plan, list every co-occurring condition. Use that count to justify more hours, smaller ratios, or assistive tech. Do not bank on behavior spikes; plan for skill teaching instead.
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02At a glance
03Original abstract
Numerous researchers have reported a high incidence of additional disabilities coexisting with intellectual disabilities. Although an intuitive link can be made between the existence of multiple disabilities and greater need for support, little has been reported about this relationship. Using measures of adaptive functioning and support needs, we examined the extent to which adaptive and challenging behaviors and consequent support needs (including medical) were impacted by the presence and severity of additional disabilities for individuals with intellectual disabilities. Results show that adaptive behaviors and support needs were meaningfully related to the number and severity of additional disabilities present, whereas this was not so for challenging behaviors. Findings are discussed in terms of contemporary models of disability and functioning.
American journal on intellectual and developmental disabilities, 2009 · doi:10.1352/1944-7558-114.4.237-253