Two new autism studies raised conflicting thoughts among parents of autistic children on Monday. One study suggested that children diagnosed with autism were able to outgrow the mental disorder, and another study found that changing the definition of autism could leave out thousands of patients who currently qualify for a diagnosis of autism spectrum disorder.

A study released in the journal Pediatrics suggested that some children diagnosed with autism no longer had the disorder when later evaluated, possibly because they originally had other issues like anxiety, depression or hearing disorders.

Researchers from Johns Hopkins Bloomberg School of Public Health reported that about 26 percent of parents of children between the ages of three and five-years-old with the disorder reported a change in diagnosis. Nearly 34 percent of parents of children aged six to eleven and 35 percent of parents of children aged twelve to 17 reported their child had been diagnosed with autism at some point but longer was considered to have autism.

Researchers said that children with two or more co-occurring developmental or mental conditions were five times more likely than children with fewer coexisting conditions to maintain an autism diagnosis.

Children were eleven times more likely to continue to have an autism diagnosis if they had a moderate-to-severe learning disability, while children with developmental conditions were nine times more likely to retain an autism diagnosis.

Another study that raised concerns among many parents with autistic children suggested that the recently proposed changes in the definition of autism would significantly reduce the proportion of children diagnosed with autism. Study author Dr. Fred Volkmar and director of the Child Study Center at Yale University said that the proposed changed could make getting get health, educational and social services more difficult for the numerous people who no longer meeting the disorder criteria.

“Given the potential implications of these findings for service eligibility, our findings offer important information for consideration by the task force finalizing DSM-5 diagnostic criteria,” said Volkmar in a meeting of the Icelandic Medical Association last week.

Volkmar found that approximately half of the individuals diagnosed with autism and had no intellectual disabilities during 1994 Diagnostic and Statistical Manual of Mental Disorders field trial would not qualify for an autism diagnosis under the proposed definition changes to be implemented in 2013.

Yale researchers stressed that these findings are associated only to more cognitively able individuals and may have less of an impact on diagnosis of more mentally disabled people.

“Use of such labels, particularly in the United States, can have important implications for service,” Volkmar said. “Major changes in diagnosis also pose issues for comparing results across research studies.”

The Yale study will be published in April in the Journal of the American Academy of Child and Adolescent Psychiatry.