Correction appended, Feb. 16, 2016
After reviewing the existing studies on autism screening, the U.S. Preventive Services Task Force (USPSTF), a group of experts tasked by the federal government to review medical studies and provide recommendations for the public, said Tuesday in a statement in JAMA that there is not enough evidence to recommend all infants be screened for the developmental disorder.
This adds to growing contention among experts about which babies should be screened for autism, with the new USPSTF recommendations disagreeing with those from other prominent medical groups, including the American Academy of Pediatrics (AAP). Autism is usually diagnosed in children who are around age 2, when the symptoms of the disorder are first noticed by a parent, teacher or doctor. But by that time, some experts say, autism may be harder to treat. Researchers have been working on ways to detect and diagnose the condition in younger babies, when behavior-based interventions might be helpful in minimizing some of the symptoms or even reversing them, but the evidence so far is not strong enough for the USPSTF to recommend screening for all infants 18 to 30 months old.
The task force found that while the common screening tools—the most popular of which is a parent questionnaire that assesses children’s communication and attention skills—is effective, none of the studies looked at a general population of infants to see whether the screening could detect autism and lead to effective treatments in them as well.
“This demonstrates progress in the field,” says Dr. David Grossman, vice chair of the USPSTF and senior investigator of Group Health Research Institute in Seattle. “Ten to 15 years ago, there was not sufficient evidence to say that the screening tool correctly identified children at higher risk of developing autism.”
Still, that doesn't prove the screening will identify non-high-risk babies, nor does it prove that treating those babies earlier will reduce the severity of their symptoms or avoid the disorder altogether. “It doesn’t mean that the screening isn’t effective and that in fact these interventions do not work in these children. It’s just that we don’t know,” Grossman says.
That's why the USPSTF says that, for now, there is not enough evidence to support universal screening of infants for autism. What the group says is still missing is a long-term study looking at a large number of children in the general population over time. Such studies would have to compare those children who are screened with those who are not—as well as track the outcomes of those who are diagnosed with autism and then go on to get treatment.
The USPSTF's conclusion is expected to generate disappointment among some parents and autism experts—as well as confusion. The AAP, for instance, recommends autism screening for all infants, and the American Academy of Neurology and the American Academy of Child and Adolescent Psychiatry advocate general developmental screening and more detailed autism screening if those first evaluations raise questions.
For its part, the AAP “is not planning to change our recommendation to pediatricians,” says Dr. Carolyn Bridgemohan, a member of the AAP autism subcommittee and co-director of the autism spectrum center at Boston Children’s Hospital. “We will continue to recommend that children should be screened at specific ages for developmental delays but also at specific ages to identify possible autism spectrum disorder.”
"I think the task force recommendations are going to create confusion,” says Dr. Geraldine Dawson, director of the Duke University center for autism and brain development. “We are also concerned that because the general pediatrician is already so busy, if there is any question that screening is not necessarily helpful, then the pediatrician may just say 'I don’t need to do this.' That is going to be really unfortunate."
Making matters more confusing, the AAP and USPSTF looked at the same data; they just came to different conclusions about the strength of that data. "It has been shown that universal screening leads to earlier diagnosis," says Dawson, "And we know that earlier access to intervention [after diagnosis] leads to better outcomes. So A is shown to be linked to B, and B has been shown to be linked to C. What the USPSTF wants is to show that A is linked to C.” Dawson says that may be a high bar to cross.
The AAP continues to recommend screening of all children for any signs of the disorder.
Grossman says that if pediatricians are already screening every child they see, there’s no harm in continuing the practice. Most of the therapies that doctors recommend if children do test positive are behavior-based, and don’t come with serious side effects of negative consequences. “But what we’re saying is that there may be benefit, but we don’t know,” he says of these treatments.
He also hopes that doctors will see this as an opportunity to advocate for more research into this question, and encourage their patients to participate in studies that could provide more meaningful answers to the questions of how effective universal screening might be.
“I see it as a call for more research as opposed to something in the short term that is going to steer clinical practice,” says Dr. Michael Silverstein, vice chair of research in the department of pediatrics at Boston University School of Medicine. “We as a pediatric community have to deal with the inconclusive recommendation [from the USPSTF] in the short term so we can have better practices in the long term.”
Correction: The original version of this story incorrectly described research of screening for autism in children. No studies have looked at autism screening in all children and whether such screening can lead to effective treatments.