CLEVELAND, Ohio -- Casey Camp-Horinek watched heroin and opiate addiction sweep though her Oklahoma tribe over the past decade, changing members into what she described as "walking zombies."

Camp-Horinek, one of more than 3,000 members of the Ponca Tribe of Oklahoma, said members of her tribe turned to drugs for various reasons, including mistreatment by the government, environmental problems and having a lower standard of living than other parts of the country.

Many got addicted simply by listening to their doctors.

"I think it snuck up on us," Camp-Horinek said. "I think the fact that you are dealing with something that's being prescribed by your medical caretaker made us believe that everything would be OK."

Native American tribes across the country have filed or are considering filing lawsuits against drug companies over the nation's opioid epidemic. These suits, which includes one filed by the Ponca Tribe of Oklahoma, seek to recoup costs for social services and other programs the tribes funded as a means to treating record-high addiction rates among Native Americans.

They say the drug companies undertook a misleading and aggressive marketing effort that downplayed the addictive nature of prescription opioids.

A federal judge in Cleveland is overseeing the lawsuits, along with hundreds of others filed by cities, counties, states and unions from across the country. Defendants in the cases include Purdue Pharma, AmerisourceBergen and the Ohio-based Cardinal Health. He has pushed all sides to reach a settlement, but has allowed for discovery and set the first trial for March 2019.

The lawsuits filed by the Ponca and other tribes are different, according to David Domina, an attorney for several federally-recognized tribes in Nebraska. As such, they should be treated differently and grouped together, he says.

"History, culture, predominant religious practices, significant health practices, abbreviated longevity, lower average user age, elevated usage levels, and historical problems with addictions, all make problems of tribal governments unique," Domina wrote in a brief filed Monday.

Right now, certain states, hospitals and third-party payers are grouped together as the cases are litigated. Native American tribes are lumped into a group with the state of Alabama.

The parties have until Aug. 17 to submit a plan to group more cases together for what are called "litigation tracks," which Domina and others hope includes one for the tribes.

Domina, who represents the Omaha, Ponca and Winnebago tribes of Nebraska, and the Santee Sioux Nation, said in an interview that grouping the tribes' cases together would provide focus for issues that affect the tribes but not the other government entities suing the drug companies.

He said the tribes' claims are distinct because their doctors are generally provided by Indian Health Service, a division of the U.S. Department of Health and Human Services. Domina's brief also says there are also medical and cultural issues surrounding Native Americans that warrant the cases being grouped together.

Brendan Johnson, a Sioux Falls, South Dakota attorney representing several tribes in the opioid litigation, said the tribes are recognized as sovereign nations, which also makes their opioid lawsuits unique.

Of the hundreds of lawsuits filed against drug companies being heard in Cleveland, more than 20 were filed by Native American tribes, though more are expected. None originate from Ohio, as the state does not have any federally or state-recognized tribes.

While the number of cases is small, the federal government has said the opioid epidemic has disproportionally affected the members of the 550-plus federally-recognized tribes nationwide.

The Centers for Disease Control and Prevention says American Indians and Alaska natives had the highest drug overdose rates in 2015 of any American ethnic group, according testimony given to the U.S. Senate's Committee of Indian Affairs in March by Dr. Michael Toedt, chief medical officer for the Indian Health Service.

Deaths increased more than 500 percent between 1999 and 2015, the largest increase when compared to other ethnic groups, Toedt testified. Those statistics might not account of a number of deaths that went unreported, as some death certificates do not list the correct ethnicity of many Native Americans, he said.

Drug companies have maintained that painkillers such as Oxycontin have legitimate medical uses approved by the U.S. Food and Drug Administration.

Camp-Horinek, the Ponca Tribe of Oklahoma member who also sits on the tribe's business committee, called the drug companies "predators." She said she sees the effects of addiction in her community, from crime to child welfare issues.

"Each and every family I speak to has a personal story about a family member that has become addicted," she said.

Her family is no exception. Her former son-in-law hurt was hurt at work when a truck in which he was a passenger flipped. He underwent several surgeries and eventually got hooked on painkillers.

When the prescriptions dried up, her son-in-law switched to methamphetamine and then heroin. Camp-Horinek said her family "lost him entirely," and that the painkillers turned a decent man with a lot of cultural pride into an addict who is only looking for his next fix.

"He's still alive but he's no longer living in that pitiful body there," Camp-Horinek said. "A shell of a human being there that used to be a loved family member, and is now someone that's only about feeding his addiction. It's like a death."

Camp-Horinek said the tribe would use any money from the opioid litigation - should it ever come - for programs that treat addiction.

U.S. District Judge Dan Polster, a Cleveland federal judge who is presiding over all the cases in U.S. district courts, said at a May 10 hearing that "the tribes are an important part of this litigation. They have been, I think, disproportionately affected by the opioid epidemic and I've made very clear if there is a resolution there won't be one without them."

Paul Hanly, Joe Rice and Paul Farrell, who serve as lead counsel for the hundreds of plaintiffs in the case, said in a statement that "the tribes are an important component of any solution and we support Judge Polster's statement that they will not be overlooked nor forgotten.

"Every plaintiff will eventually have the opportunity to be designated in a case track."

Mostly, though, the tribes just don't want to be forgotten, their attorneys said.

Johnson said the tribes worry about this because they were not part of the litigation and eventual settlement state governments reached with Big Tobacco in the late 1990s. The opioid litigation is frequently compared to the lawsuits filed against Big Tobacco.

"Here the tribes have stood up and demanded to have a voice," said Johnson, who served as South Dakota's U.S. attorney under President Barack Obama. Among the tribes he represents in South Dakota include the Flandreau Santee Sioux and the Rosebud Sioux tribes and the Sisseton Wahpeton Oyate of the Lake Traverse Reservation.

Camp-Horinek doesn't think the tribes forgotten, but rather that it was "deliberate," citing grievances about historically bad treatment by the federal government. That said, she said her tribe has been resilient after one crisis after another, be it environmental, government, drugs or otherwise.

"We have somehow found a way to live," she said.