A Longitudinal Study of Aggression in People with Autism and Other Neurodevelopmental Disabilities.

The sample was large overall, but some analyses used smaller groups, especially CBCL and change across consecutive time points. Participants were recruited in the early 1990s, so today's children may have different supports, diagnoses, and outcomes. The study could not control for unequal loss of participants by race and maternal education. It did not follow participants into middle or older adulthood. Age 2 aggression included tantrums, so it may not mean the same thing as later aggression. The ADOS was only a short observation, so aggression may be missed outside the clinic. The aggression measure was yes/no, not how often or how severe aggression was. No treatment was tested, so changes over time cannot be attributed to therapy or services.

Do not read the decline as proof that treatment worked. No intervention was tested. Also, do not assume toddler aggression predicts later aggression. In this sample, aggression at age 2 did not predict aggression at age 9 or 18.