There has been much discussion as to why the rate of autism has been steadily increasing since the 1990s. One reason is linked to the change in diagnostic nomenclature in 1994. At that time, the diagnostic criteria for autism expanded to include children who were not previously considered “on the spectrum.”
Studies have shown that, despite this change in diagnostic criteria, the number of diagnosed cases of autism spectrum disorder (ASD) is much higher than expected (Johnson & Myers, 2007). Many researchers believe the increase in the number of cases of autism worldwide is due to a combination of genetic and environmental factors.
Researchers are working diligently to seek answers for families about the cause of autism.
Current facts about autism:
- It aﬀects 1:59 children nationwide (Centers for Disease Control and Prevention).
- It can be found in all cultures of the world, and does not discriminate based on race, socioeconomic status, education of parents, or other demographic variables (Wong, Hui, & Lee, 2004; Howlin & Asgharian, 1999).
- It is almost four times more likely to occur in boys than girls.
- Approximately 10 percent of children with ASD have an identiﬁable genetic or chromosomal disorder (i.e., fragile X or tuberous sclerosis).
- It currently has no known cause or cure.