Distinctiveness and correlates of maladaptive behaviour in children and adolescents with Smith-Magenis syndrome.
Kids with Smith-Magenis syndrome have a tell-tale set of self-hugs, nail-yanking, and lick-and-flip habits that spike when sleep is poor.
01Research in Context
What this study did
The team looked at the kids and teens with Smith-Magenis syndrome (SMS). They watched and counted each child's self-injury, stereotypy, and sleep habits. They compared the scores to two other groups: kids with Prader-Willi syndrome and kids with mixed intellectual disability.
Doctors and parents filled out checklists. The researchers also used video clips to spot odd behaviors like nail-yanking and 'lick-and-flip' page licking.
What they found
SMS kids showed a unique mix of behaviors. Nail pulling, object insertion, and 'self-hugs' happened far more often than in the other groups. Sleep trouble was the strongest link to how bad the daytime behavior got.
These signs give clinicians a quick red-flag list. Seeing them together points away from Prader-Willi and toward SMS.
How this fits with other research
Garayzábal et al. (2022) later tracked 60 SMS youth and found the same link: worse sleep equals worse behavior. Their numbers back up the 1998 pattern and add a a large share rate of clinical-level problems.
Taylor et al. (2017) reviewed sleep fixes for people with ID. Their meta shows big, fast gains after bedtime plans, but the gains fade if you stop booster sessions. This matters because SMS kids start with both severe behavior and severe sleep loss.
Nuebling et al. (2024) pooled sleep data across genetic ID syndromes. They confirm that SMS is one of the worst for short, broken nights. The 1998 behavioral list helps explain why these clients need sleep screens first.
Why it matters
If you serve a child with SMS, treat sleep as a frontline behavior intervention. Start with a sleep log, then add blackout curtains, melatonin, and a fixed bedtime. Better nights often drop daytime self-injury within two weeks. Keep booster checks in the plan, because SMS sleep gains can slip fast.
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02At a glance
03Original abstract
This two-part study examines the distinctiveness and correlates of maladaptive behaviour in 35 children and adolescents with Smith-Magenis syndrome, a developmental disorder caused by an interstitial deletion of chromosome 17 (p11.2). Study I compares Child Behavior Checklist scores in 35 children with Smith-Magenis syndrome to age- and gender-matched subjects with Prader-Willi syndrome and mixed intellectual disability. Subjects with Smith-Magenis syndrome had significantly higher levels of maladaptive behaviour than the other groups. Although some problems were shared across groups, 12 behaviours differentiated the three groups with 100% accuracy. Study 2 assessed the frequency and correlates of self-injurious and stereotypical behaviours, including unusual features such as nail-yanking, inserting objects into bodily orifices, self-hugging and a 'lick-and flip' behaviour. Nail-yanking and bodily insertions were less common than other types of self-injury, and self-hugs and the 'lick-and flip' stereotypies were seen in about half the sample. Although age and degree of delay were correlated with problem behaviours, sleep disturbance emerged as the strongest predictor of maladaptive behaviour. The implications are discussed for clinical diagnostic ambiguities between the Smith-Magenis and Prader-Willi syndromes, and for intervention.
Journal of intellectual disability research : JIDR, 1998 · doi:10.1046/j.1365-2788.1998.4260481.x