More intervention hours may not always lead to improved outcomes for children with autism.

That’s according to a new meta-analysis published in JAMA today. Researchers analyzed data from 144 studies of early childhood autism interventions, which included a total of 9038 children.

“There is not robust evidence that the benefits of early childhood interventions to young autistic children increase when those interventions are intensified; practitioners recommending interventions should consider what amounts would be developmentally appropriate,” authors of the study wrote.

The study divided intervention time into three categorizations: intensity, which refers to the number of hours provided within a given time frame; duration, which refers to the total number of days that the intervention is provided; and cumulative intensity, which combines the metrics to calculate the total amount of intervention time provided.

Researchers constructed meta-regression models to determine efficacy. The study found that “none of the meta-regression models evidenced a significant, positive association between any index of intervention amount and intervention effect size when considered within intervention type,” according to the study. 

However, authors of the study stressed that it is still important for children with autism to get the right resources.

“Although we did not find evidence that increasing amounts of intervention were associated with increasing benefits, this should not be interpreted as evidence that autistic children should be left without support,” authors of the study wrote. “Multiple high-quality studies in our sample attested to the effects of some intervention approaches offered at various intensities for young autistic children.”

Researchers went on to say that it is “likely that there is a minimal amount needed for intervention to have any benefit” and that the amount of services could be based on the child.

According to the CDC, 1 in 36 children have been diagnosed with autism spectrum disorder. Applied behavioral analysis (ABA) is typically recommended as the gold standard of therapy for children with autism.

Still, there is a lot of variation when prescribing and reimbursing the number of ABA hours. Across the country each payer has its own reimbursement parameters and providers have their own assessment criteria for prescribing hours.

Authors of the study noted that intensive autism interventions are generally provided for a minimum of 20 hours a week and up to 40 hours a week for at least 2 to 3 years. Still, the exact amount a child should be in services varies from provider to provider and location to location.