Desperate parents of out-of-control teens increasingly have turned to therapeutic, or "emotional growth," boarding schools that often blend outdoor adventures with psychotherapy and academics.

But the abrupt shutdown of one of the field's most prominent operators last week amid lawsuits alleging student abuse is raising concern about the quality and financial stability of these little-regulated, high-priced schools.

Last Friday Brown Schools Inc., the closely held owner of one of the nation's best-known therapeutic boarding chains, closed with no notice to families, sending 300 students home before the end of the school year. Brown -- which operated five boarding schools in Idaho, California and Vermont, plus other youth programs in Idaho, Texas and Florida -- filed for bankruptcy under Chapter 7, meaning its operations will be liquidated.

Fenton R. Talbott, who served as chief executive of Brown before the bankruptcy filing, said the company has had trouble paying its high debt, and was unable to secure more financing, leading to the schools' end. Mr. Talbott said the school faced high legal fees and settlement costs related to a variety of lawsuits, including some on behalf of students and families alleging abuse. "We had no choice," Mr. Talbott said of the bankruptcy, declining to discuss details.

Based in Austin, Texas, Brown is part of a fast-growing industry. The National Association of Therapeutic Schools and Programs lists 140 schools and programs, up from 43 in 1999. The schools generally charge $30,000 to $50,000 per academic year, with some parents receiving some funds from health insurance or local school districts that may be obligated to pay when they can't provide comparable services.

Hardly the boot-camp style facilities long associated with troubled teens, these schools for the most part blend vigorous outdoor activities such as horseback riding or mountain hikes with some level of therapy and an academic curriculum. Some are independent, such as Montana Academy, a co-ed school on a working ranch that caters to teens who are depressed or dabbling in drugs, among other issues. Others, such as Auldern Academy in Siler City, N.C., are units of larger for-profit ventures such as Three Springs Inc., Huntsville, Ala., which operates nearly 30 programs from boarding schools to "outdoor treatment centers" situated in woodsy camp-like settings. Another big operator is closely held Aspen Education Group Inc., of Cerritos, Calif., which has 30 programs in 11 states.

Depending on the level of therapy offered, staffing can range from unlicensed "peer counselors" to on-site psychiatrists who can monitor medication such as antidepressants.

The growth comes as military schools seem to be losing favor as parents seek softer approaches. The number of all-boys military boarding schools has steadily declined during the past decade, says William Trousdale, a curator emeritus for the Smithsonian Institution who researches them. In part the shift also reflects the lessening stigma for psychotherapy and the increasing number of young people on behavioral medications, educational consultants say. The number of children on such drugs jumped more than 20% to nearly 16,000 in 2003, from about 13,000 in 2000, according to a study of 300,000 members of pharmacy-benefit manager Medco Health Solutions Inc.

But while therapeutic schools have grown in popularity, many educational experts also caution that treatment approaches and quality vary widely. There is little, if any, large-scale, independent research to be found on how effective these schools are in helping troubled kids. And while residential treatment centers are typically accredited by a health-care organization, there is no national accreditation system specifically for "therapeutic" boarding schools. Parents must look to a patchwork of academic and health-care licenses and accreditations to judge quality.

Executives at these companies and the trade association say financial problems and complaints about mistreatment at Brown facilities are anomalies.

Still, Mark Sklarow, executive director of the Independent Educational Consultants Association in Fairfax, Va., says Brown's shutdown is generating "genuine concern" among parents and consultants because it can be difficult for consumers to tell whether a program is financially stable. Mr. Sklarow, whose group represents consultants who help families find private schools, says a dozen or so therapeutic programs close a year, but Brown's end was unusually sudden and took down a pioneer.

Industry officials often credit Brown's main operating unit, CEDU Education, with founding the therapeutic movement to help troubled teens during the 1960s. A Brown Web site says the name stands for "See and do," or to "see yourself as you are and do something with it." Founded in 1940, Brown once focused on residential treatment centers for troubled kids before it bought CEDU in 1998. With stunning mountain settings and price tags rivaling private colleges, the Brown schools in Idaho once attracted a celebrity clientele. Prominent graduates include the daughter of newscaster Barbara Walters.

This week, parents got a shock. Charlotte Adamis, parent of a 14-year-old student at Brown's CEDU Middle School, in Running Springs, Calif., said the company was helping her child get over severe behavior problems that led to fights and school failure. But, at 4 p.m. last Friday, she says the staff learned the school was closing and families were told their kids had 24 hours to leave the campus. Her family had prepaid $12,000 in tuition and will have to line up with creditors to see what, if anything, they will get back in the bankruptcy. She said the tuition was $60,000 a year.

Ms. Adamis, a school librarian in Kingston, N.Y., now worries her son will suffer from "broken trust" because of the school's abrupt shutdown. "I'm furious, and I'm heartbroken," she says.

In a statement, Brown's controlling investor, private-equity firm McCown De Leeuw & Co., of Menlo Park, Calif., called the closure "unfortunate." Spokesman Sam Singer said that Brown's debt was incurred when the company bought the CEDU chain in 1998 for $78 million, which he said was too high a price. McCown officials expressed hope that buyers could be found for individual schools. The company's King George School in Sutton, Vt., remains open while Karen Fitzhugh, head of the school, tries to find a way to keep operating; she says a parent has made an offer to buy it.

Brown, in its court filing, cited a total of $1.4 million in legal fees and settlement costs, including a pair of $150,000 settlements paid to two former residents of Brown's Oaks Treatment Center in Austin, Texas, a facility for adolescents with behavioral and other problems that Brown sold in 2003. In a lawsuit filed in state court in Austin, the students alleged they were sexually assaulted in 2002 by an Oaks employee, who ultimately pleaded guilty to assault charges, according to court papers. The company denied liability.

Court papers didn't mention some other legal tangles in Brown's past. In 2002, Chase Moody, 17, died at a Brown wilderness program called On Track, in Texas, after being restrained by camp staff members. State regulators said that staffers used improper restraints, but a grand jury handed up no criminal charges.

Also that year, CEDU paid a $300,000 settlement to two former students after they were hurt in what students at the time describe -- and the company confirmed -- was a riot at CEDU's Northwest Academy in Bonners Ferry, Idaho. The company didn't acknowledge liability.

Last October two dozen parents and former students at two CEDU schools in Idaho, Rocky Mountain Academy and Boulder Creek Academy, filed four lawsuits alleging poor staffing levels that led to verbal and physical abuse by students and employees since 1998. The cases are pending in Bonner County District Court in Sandpoint, Idaho. McCown's Mr. Singer says the firm "believes the allegations have no merit whatsoever."

Another organization of these types of schools also faces scrutiny. Rep. George Miller (D., Calif.) has written letters to both State and Justice Department officials urging more investigations of seven programs in the U.S. and abroad that are part of the World Wide Association of Specialty Programs and Schools. Staffers say he is looking to introduce legislation in the next month to improve oversight of such programs, which he says have been involved in instances of abuse.

Ken Kay, president of the World Wide group, based in St. George, Utah, says, "There has never been any substantiated cases of abuse or mistreatment." But he added that two employees, each at different programs in Montana and Utah, were dismissed for endangering child safety. He said there were no serious injuries.

Edward Hallowell, a child psychiatrist based in Sudbury, Mass., and a retired Harvard instructor, advises that parents work with reputable education consultants who specialize in placing troubled kids to fund strong programs.