AUSTIN – The number of children living in state schools for the disabled has grown by 80 percent in the last five years, a trend advocates say threatens decades of work to move Texas' most fragile youths back into family homes.

It's the result of hopelessly long waiting lists for services at home. Of school districts unable to serve a growing number of autistic students. And of communities too quick to turn youths with mental illness over to the courts.

Recent news that the U.S. Department of Justice is investigating the Denton State School – the second federal inquiry into a state school in two years – is fueling the fire for those who think state institutions are no place for juveniles.

And while state officials say they only house these youths until they can find them permanent family homes, opponents point to signs that state schools are getting too comfortable with their new charges – from building campus playgrounds to cordoning off child-only dorms.

"We need to be able to stop it at the front door," said Colleen Horton, the public policy director for the University of Texas' Center for Disability Studies. "I've never ever heard a family say, 'I want to place my child in a state school.' What I have heard is, 'We are at the end of our rope, we can't get any help, our family is falling apart and we just can't do it any longer.' "

In the months before Douglas and Stormi Toomes did what to them was unthinkable – they admitted their small, sandy-haired son to a state school – the couple locked every door in the house at night, fearing what Dakota might do while they slept.

The bipolar and severely mentally disabled 16-year-old slammed his head into brick walls. He terrorized his classmates and warned he'd burn down his school. He beat and threatened to kill his family.

"I felt like a father that had let my son down. I felt so much guilt inside that it's almost unexplainable," said Mr. Toomes, sharing burgers and fries with a goofy, grinning Dakota on an Easter Sunday visit to the Austin State School. "We had no choice. We were living in this isolated world, where there was no help, no patience, no care for a kid like Dakota."

Proportionally, children under 18 are a small piece of the state school equation; they make up just 3 percent of the population. But while the total number of adult residents has dropped in recent years, the number of youths continues to grow. It costs the state about $100,000 a year to care for a patient in the state schools, compared with about $50,000 for community-based care.

Of the children admitted to the state school system in 2007, three-quarters of them had a diagnosis of autism or mental illness, advocates say. Some were as young as 8.

This upswing frustrates opponents of Texas' institutionalized care, many of whom hoped the state schools would be phased out as their older residents aged. Over the past year, Dallas Morning News investigations have uncovered reports of severe abuse, neglect and vile conditions at some of the worst state institutions.

And it angers advocates for the disabled, who believe every child should be in a personalized, home environment. Since 2001, the Texas Legislature has required the state to seek permanent homes for anyone under age 22 living in an institution.

Addie Horn, the commissioner of the Texas Department of Aging and Disability Services, said in a hearing last month that children living in state schools are "temporary placements" whose cases are reviewed every six months. Roughly 60 percent of youths under 18 – who have an average length of stay of a year and four months – are expected to return to their family homes. The rest are slated to live with alternate families.

But advocates for independent living say these kids aren't moving out as fast as they're moving in – the result of a lack of options and funding for community-based care. Jeff Garrison-Tate, president of the nonprofit Community Now!, said he's visited state schools with playgrounds and "little boys and little girls units," some of which had bars on the windows. These are facilities that also house adults with cognitive and behavioral disabilities, he said, which could put the younger residents at risk.

State school officials refuse to comment on any child-specific facilities or programming, citing client privacy. But they acknowledged they're holding meetings with advocates to try to curb the increase in youths entering the state schools.

"We don't have programs based on certain ages," agency spokeswoman Laura Albrecht said. "We serve individuals' needs, and we're very dedicated to that."

For the Toomeses, who live in South Texas, the Austin State School has provided relief – at last. Dakota is "no longer an outcast," they say – he's in a loving, professional setting surrounded by young boys he can relate to. And the family is done fighting legal battles with the local school district, which they said tried repeatedly to press criminal assault charges against Dakota.

"For years, we wouldn't attend a birthday party. We wouldn't go out to eat at a restaurant. Everyone would look at us like we were parents who didn't know how to raise a child," said Mr. Toomes, a highway construction worker. "I know a lot of people think we've given him up to the state, that this is a throwaway place. Well, I wish I would've known about it 14 years ago."