CLEVELAND (AP) — Guardians caring for hundreds of thousands of children born dependent on opioids since 2000 should be grouped together as part of the class action lawsuit filed by local governments and others against the manufacturers, distributors and sellers of prescription pain medication, lawyers argued in a motion filed in federal court in Cleveland.

In addition to certifying the guardians as a class, the attorneys who filed the motion Tuesday want U.S. District Judge Dan Polster to create a national registry to identify children diagnosed with neonatal abstinence syndrome, form a medical panel to recommend the best ways to treat such children, and provide money for those efforts as quickly as possible.

“The urgency of this is, the longer we wait, the more difficult it is to help these children,” said Cleveland attorney Marc Dann, who filed the motion along with attorneys from Texas and Louisiana.

There currently are about 400 guardians for children born dependent on opioids who have filed individual claims in the pending lawsuit that Dann said could be folded into the larger group. The motion filed this week was made initially on behalf of a handful guardians in Ohio and California and seeks to include guardians from across the country, he said.

The total number of children born dependent on opioids since 2000 is around 400,000 with between 20,000 and 30,000 NAS babies born each year, Dann said

Some states have created registries for children diagnosed with NAS while others have not, Dann said. In most cases, the children's guardians are grandparents or someone who has been appointed to that role.

A national registry would allow scientists to accumulate more data to refine how best to treat these children at each stage of their development, Dann said.

Research has found that children born dependent on opioids suffer from developmental delays, medical problems and are susceptible to becoming addicts themselves as they grow older, Dann said.

“We haven't started this process as a society to figure this out,” he said. “It's a large effort, no question, to get there.”

As do other plaintiffs in the class action lawsuit, attorneys for the guardians seeking to be certified as a group allege the pharmaceutical industry engaged in a conspiracy to increase the number of people addicted to prescription painkillers, a claim the industry has denied in court and in motions.

“Over time, as science disproved the claims of the pharmaceutical industry, those parents were driven to the streets to buy manufactured opioids or heroin,” Dann said. “They went from being customers of doctors to customers of the cartels.”