Over the past 50 years, the number of people with autism has continued to rise. Today, 1 in 54 children is on the spectrum, according to the CDC. Research suggests that genetic and environmental contributions to autism have remained consistent over time; therefore, the surge may be due to increased awareness and diagnostic shifts.
The DSM-IV, which was used before 2013, contained three categories: autistic disorder, Asperger’s disorder, and pervasive developmental disorder not otherwise specified. The DSM-5 replaced those categories with one overarching diagnosis: autism spectrum disorder. Such changes in the criteria likely resulted in additional people receiving an autism diagnosis. Additionally, both families and clinicians today are likely more aware of autism and its symptoms than in past decades, making diagnosis more likely.