Prevalence, phenomenology, aetiology and predictors of challenging behaviour in Smith-Magenis syndrome.
In Smith-Magenis syndrome, aggression is present in a large share and is driven by social reinforcement and impulsivity—assess these functions first.
01Research in Context
What this study did
Doctors asked the families who have Smith-Magenis syndrome (SMS) to fill out long forms. The forms asked about hitting, biting, yelling, and other tough behaviors.
The team also looked at medical charts and gave short IQ tests. They wanted to know how many kids showed aggression and what kept it going.
What they found
Almost 9 out of 10 people with SMS had hit, kicked, or hurt others. The mean age was 11, but the behavior started as early as age two.
Most outbursts got loud adult attention or escape from tasks. Quick mood swings and poor impulse control made the bursts worse.
How this fits with other research
Lyall et al. (2012) saw the opposite link in toddlers with ASD. Higher IQ meant more behavior problems in that group, but lower IQ meant more problems in non-ASD kids. SMS fits the second half: lower IQ plus very high aggression.
Cryan et al. (1996) tracked fragile-X boys and found their daily skills grow until age 10, then stall. SMS shows a different path—skills may grow, but aggression stays high across all ages.
Gaylord-Ross et al. (1995) showed teens with mild ID try harder tasks when we praise effort. SMS kids have more severe ID and impulse issues, so simple social praise alone may not cut it.
Why it matters
If you serve a client with SMS, expect hitting or biting to show up early and stay. Start a functional assessment right away. Look for adult attention or escape as the payoff, then add impulse-control tools like response-cost or visual wait cards. Do not wait for the child to outgrow it—the study says the behavior sticks around.
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02At a glance
03Original abstract
BACKGROUND: The prevalence, phenomenology aetiology and correlates of four forms of challenging behaviour in 32 children and adults with Smith-Magenis syndrome (SMS) were investigated. METHODS: Cognitive assessments, questionnaires and semi-structured interviews were used to gather data on intellectual disability, verbal and physical aggression, destructive behaviour and self-injury and on characteristics known to be associated with aggression. RESULTS: Aggression in SMS was more prevalent (87%), but not more severe than aggression in contrast groups. Aggressive behaviour was more frequently associated with environmental contingencies (e.g. attention, escape and access to tangibles) than self-injury and destructive behaviours. Severity of challenging behaviours was associated with high impulsivity. CONCLUSION: Aggression is seen in the majority of people with SMS. Results suggest that behavioural disinhibition and operant social reinforcement are associated with the manifestation of aggression.
Journal of intellectual disability research : JIDR, 2011 · doi:10.1111/j.1365-2788.2010.01371.x