Factor structure of maladaptive behavior across the lifespan of persons with mental retardation.
Behavior-rating factors move with age and ID severity, so match the norm sample to your client or risk mis-reading the score.
01Research in Context
What this study did
The team ran a factor analysis on behavior-rating forms from over 8,000 people with intellectual disability. They looked at every age group and every level of ID severity.
The goal was to see how many different ‘kinds’ of maladaptive behavior show up and whether the pattern changes with age or IQ level.
What they found
The data broke into up to six clear behavior clusters. The exact clusters shifted depending on how old the person was and how severe the ID was.
In plain words, the same score on a behavior scale can mean different things for a teenager with mild ID versus an adult with profound ID.
How this fits with other research
van Timmeren et al. (2016) later built on this work. They focused only on adults and found two main dimensions: emotion dysregulation and depression/anxiety. This narrows the six-factor view for the adult slice of the lifespan.
Ganz et al. (2004) surveyed staff and found psychiatric symptoms drop off in severe/profound ID. That lines up with Christopher et al. (1991): when ID severity changes, the behavior map changes.
van Timmeren et al. (2016) systematic review warns that many later factor studies use weak stats. The 1991 giant sample still stands as solid footing.
Why it matters
Before you trust a behavior scale’s cut-off, check the age and ID-severity range used to norm it. If your client falls outside that group, the ‘clinical’ score may be a false alarm. Pick tools with matching norms or interpret with extra caution.
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02At a glance
03Original abstract
Data obtained on a sample of persons with mild to profound degrees of mental retardation (N = 8255) and ranging from birth to 98 years of age were factor analyzed to provide information on the structure of maladaptive behavior relative to age and degree of mental retardation. Using the Problem Behavior scales of the Inventory for Client and Agency Planning, two principal factors emerged for children with mild to profound degrees of retardation: Internalized Maladaptive and Externalized Maladaptive. For adolescents and young adults, a three-factor solution which varied by degree of retardation was most appropriate. For middle and older adults, three- and four-factor solutions were identified across all ages and degrees of retardation. Across all samples as many as six different types of dimensions were identified, indicating that the structure of maladaptive behavior may well be influenced by age and level of mental retardation.
Research in developmental disabilities, 1991 · doi:10.1016/0891-4222(91)90005-d