A new study has been conducted by researchers at Penn State University, which reveals that autism diagnoses has increased in the US for the reason that people having other disorders have been reclassified. Earlier, the reason was thought to be an increase in number of people suffering from autism.

As per the study, researchers analyzed special education enrollment figures. It was found by them that 97% of the increase in autism that occurred between 2000 and 2010 could be a reason behind reclassification. On the other hand, some professionals are doubtful regarding this.

According to Michael Rosanoff, director of public health research at Autism Speaks, "We have known for a long time that part of the increase in autism prevalence over time is due to the shift in diagnosis and changes in the way we diagnose autism. It certainly accounts for part of the increase". However, he added that it is not responsible for the total increase.

He also said that the study only analyzed special education and education records so no information is there regarding high functioning or less affected individuals, not enrolled in special education.

According to Rosanoff, expansion of diagnostic criteria in addition to the better diagnosis of autism doesn't reveal the reason behind the increase in the disease cases over the past 20 years.

He said the increase is partly because of environmental factors, however that has to be yet analyzed and the research is heading in that direction. As per the research that has been published in the American Journal of Medical Genetics, two-thirds of the increase could be as a result of reclassification.