Researchers found that children with ASD in nine countries scored similarly on a test of their social skills whether or not they had received the music therapy.

"Music therapy - like many other interventions that have been suggested - does not improve autism symptoms," said senior author Christian Gold, of the Grieg Academy Music Therapy Research Center and Uni Research Health in Bergen, Norway.

ASDs are developmental disorders that can lead to social, communication and behavioral challenges. The U.S. Centers for Disease Control and Prevention estimates that one in 68 children in the U.S. has been diagnosed with an ASD.

The anecdotal link between music and ASD goes back many years, Gold and colleagues write in JAMA. During music therapy, a person helps a child spontaneously make music through singing, playing and movement.

There are about 7,000 music therapists in the United States and about 6,000 in Europe, the researchers write.

For the new study, the researchers recruited 364 children ages 4 to 7 years from 10 treatment centers between 2011 and 2015. The centers were in Australia, Austria, Brazil, Israel, Italy, Korea, Norway, the UK and the U.S.

All of the children received the usual care a child with ASD would receive in their region, but half of the children were randomly assigned to also get music therapy.

Usual care could range from early intensive behavioral interventions, to speech and language therapy, to sensory-motor therapies and medications, Gold told Reuters Health by email.

"Music therapy is also among the interventions that have been recommended when it is available," he said. "Some parents who are frustrated with behavioral interventions may experience it as bringing back the joy of being with their child in a natural way."

After five months of therapy, the researchers did not find a difference between the two groups of children on a measure of social skills.

Gold said parents should continue to pursue music therapy if they feel it's a good match for their children, but don't expect it to be a so-called treatment.

"Since the very first descriptions of autism in the 1940s, it has been noted that many people with autism have a special interest in music," he said. "Music therapists can help them to pursue that interest. If they also learn something about social communication through that, even better. But the pursuit of music or music therapy should not be guided primarily by the hope to reduce core symptoms of autism, because that may not be the result."

The researchers also point out that the new results conflict with a review of previous studies that was published in the respected Cochrane Library. The review found a benefit from music therapy, but the studies included in that analysis were smaller and were rated as only of low to moderate quality.

There is still room for additional research to see if music therapy may lead to benefit among some children, said Dr. Sarabeth Broder-Fingert, of the Boston University School of Medicine.

"Although the study taken as a whole makes it look like music therapy is not effective, if you pull out certain sub-populations it may work," said Broder-Fingert, lead author of an editorial accompanying the new study.

She said parents who are considering music therapy should consider the new study's findings.

"As a parent, you also have to think of the outcome that matters to you," Broder-Fingert said.

Gold added that more research is warranted.

"Efforts are already underway to improve music therapy, for example by improving their specific skills or by involving parents more actively," he said. "We should not assume that what music therapists are doing already is working well, but should try to continuously develop it further and test it."