Autism can be identified within the first 3 years of life, in some cases within the first two years. We know that autism is present from birth, but it is very difficult to identify early on because many of the signs are also present in children who do not have autism.
Some researchers look at the developmental trajectories to try and predict what will eventually be conclusively identified as autism.
Some research has shown that early intervention can play a very important role in ensuring good outcomes for the child with autism. There have been some claims that early intervention can lead to full recovery of the child with autism, but this research is focused on children who were already functioning quite well, and there were few details on the interventions used.
It is important to note that not receiving early intervention does not prevent a child from learning new skills and having an excellent outcome later in life. The key is motivation.
Use of siblings
Because younger siblings are more likely to develop autism than children who don’t have siblings with autism, a number of studies focus on these siblings to study early development.
They use this research to identify what characteristics are associated with later identification of autism.