Chronicity of challenging behaviours in people with severe intellectual disabilities and/or autism: a total population sample.

Researchers tracked every person with severe intellectual disability or autism in one region for 12 years.

They checked if early challenging behaviors stayed bad or got better as the kids grew up.

They also looked at which early skills, like talking or playing with others, predicted later problems.

Most kids saw a small drop in hitting, biting, or self-injury over the years.

But kids who started with the worst behaviors plus little speech or social play kept the most problems into adulthood.

Early language and social skills were the clearest crystal ball for later trouble.

LeBlanc et al. (2003) had already shown that very young autistic kids with daily-living delays were more likely to show self-injury. Reid et al. (2005) now prove those early red flags still matter 12 years later.

Chiang (2008) adds another layer: many non-verbal kids use challenging behavior to ask for things. So the behaviors that linger may still be their way to communicate when language is weak.

McCarron et al. (2022) shows it is possible to keep adults with ID in studies for over a decade. Reid et al. (2005) did the same for behavior tracking, proving long-term follow-up is doable.

If you see a young learners with daily tantrums and almost no words, start language and social-skills teaching now. The data say these kids are the ones most likely to still struggle at 17. Early, heavy focus on communication and play is not just good practice—it is damage control for the next decade.