The sudden presence of autism at 18 months of age following typical development.
Acquired autism is distinguished from autistic disorder, a neurodevelopmental disorder present at birth and detected through the observation of delays in language, social, and vestibular development. Acquired autism is observed when a child develops normally and then “regresses” or appears to develop autism around 18 months of age. Children receive the measles, mumps, rubella (MMR) vaccine around this age and a small body of research suggests the disorder is related to the MMR vaccine. However, a larger set of data suggests no correlation between autism and the MMR vaccine. Many factors, such as bowel problems, are thought to contribute to acquired autism, but the specific mechanisms remain unknown. The prevalence of acquired autism has been found to be between 22 and 50% ...