Because there is no known cause or origin yet, all that doctors can treat are the symptoms, and the only way to change the effects of autism on a child or adult is through management. The basic prognosis is that the autistic individual has an average life expectancy with little medical complication connected to the autism diagnosis (although about a third of autistic children develop epilepsy), but they will experience impaired social function during the entirety of that life.

There are some children who recover, in that early intervention teaches them the behaviors and skills that they need in order to lose the autism diagnosis. It is believed that this improvement is because early intervention takes place during formative developmental years - so early intervention allows an autistic individual to respond to therapy in such a way that aids the development of the brain at an adaptive time. Sometimes recovery from autism even happens on its own rather than from extensive intervention. A random sampling of autistic children show that anywhere from 3 to 25 percent of autistic children recover from the symptoms that earned them an autism diagnosis. Sometimes, even if an autism diagnosis is not removed, the symptoms become less severe over time. In general, those with high-functioning autism have a better chance of living independently and making it in a stereotypal world and have an overall better chance of improvement at all; those with low-functioning autism are much less likely to improve to the point of independence.

Most individuals with autism, though, need some kind of support all their life, whether it is family, friends, or an assisted living situation in order to properly function. It is estimated that about 60 percent of autistic individuals continue to need some kind of additional support throughout their lives. On the other hand, many individuals with autism, even if they require daily assistance, are able to get some kind of part-time or full-time job, whether it is within volunteer work or in shelters, whether they specialize in whatever their focused behavior prefers, or whether they are placed in a job through a program that helps autistic people find jobs. Even individuals with more restrictions due to lower functioning autism can learn to master skills that enable them to become employed on a certain level. So many autistic individuals can live a normal life or something approaching a normal life, with some extra assistance.

However, there is no cure for autism, due to a lack of knowledge about the mechanism of the disorder itself. No one knows the mechanism behind a formerly autistic child's recovery. Part of the problem with the question of prognosis is that not enough studies have been done since the rise in autism diagnoses, especially since diagnostics have improved only recently. In addition, early intervention for people with autism has only become an important way of managing autism in recent years. Accounts by adults with autism are few - even fewer are accounts from autistic individuals after midlife. However, there are studies still going on, and as time goes by, we can expect that the data on long-term prognosis will increase and give autistic individuals and families with autistic kids a better idea of what they can expect in their future.