I went looking for more on this in the news, like a link to the Senate hearing mentioned and the related GAO report, to discover that the reason more wasn't easy to find is that the article you posted is from Dec. 2, 2011.

Here is a Wall Street Journal piece  from the same date with more detail on the problem and the government approach:

Foster Kids Are Overly Medicated, Report Says
By Thomas Burton, Wall Street Journal, Dec. 2, 2011

Foster children on Medicaid received psychotropic drugs—including antipsychotics and antidepressants—at a higher rate than other children covered by the government insurance program, according to a federal report released Thursday.

The study by the Government Accountability Office is raising concern among lawmakers and medical experts that doctors are overprescribing psychiatric drugs to treat children in the foster-care system. [....]

The report found that drug amounts exceeding maximum doses for a child's age were many times more likely to be prescribed to foster children than to other children in the federal-state program for lower-income people. The GAO, which submitted its findings as part of a Senate hearing, also found that foster children were several times more likely than other Medicaid youngsters to be taking five or more psychotropic drugs at the same time.

Among the drugs analyzed were antipsychotics such as Abilify and Risperdal, antidepressants such as Cymbalta and Paxil, and attention-deficit hyperactivity-disorder drugs such as Ritalin and Strattera. The GAO found that foster children were between 2.7 and 4.5 times as likely to be on psychotropics as non-foster youngsters in Medicaid, depending on which state they lived in. [.....]

Foster kids often have more emotional troubles and painful pasts than other Medicaid children, but both groups can be overmedicated because they're often seen by general doctors rather than getting counseling.

"The high-risk practices identified by the GAO study raise significant concerns regarding the treatment of severely mentally ill and vulnerable youth," child psychiatrist Jon McClellan of the University of Washington told lawmakers Thursday.

Senators in both parties said federal and state agencies supervising Medicaid need to curb overprescription of the drugs.

"There is no evidence for use of five mind-altering medications in an adult, let alone a child," said Democratic Sen. Tom Carper of Delaware. Sen. Scott Brown, a Massachusetts Republican, called the findings "shocking."

Bryan Samuels, a senior official overseeing Medicaid at the federal Department of Health and Human Services, agreed that "the current use of psychotropic medications among children, particularly children in foster care, goes beyond that which is supported by empirical research." He said his department has written to state Medicaid agencies "to raise awareness of these issues."

The GAO study focused on Medicaid programs in Florida, Massachusetts, Michigan, Oregon and Texas in 2008. The GAO said 1,752 children in those programs were getting five or more such drugs at the same time.

After figuring that out, from what I saw in some more quick searches is that what appears to be in the process of happening since that hearing and report is that those states that had the highest numbers have been working on the problem, prodded by the Federal Medicaid people.

Do I need to explain that certain states like Texas aren't known to be too quick when the Feds say "jump"?

From this year's news, about working on it in Texas:

Advocates question number of foster children on psych drugs
Lt. Gov. David Dewhurst seeks investigation of claims.
 By Mike Ward, American-Statesman,  Jan. 30, 2013

A troubling proportion of Texas youths in foster care — including children as young as 3 — are being treated with psychotropic drugs, and state lawmakers must step in to curb the practice, foster care advocates warned Wednesday. [.....]

Lt. Gov. David Dewhurst, who attended the conference to join in the call for more state money, said he has ordered his staff to investigate the dosing problem and see whether changes are needed in state law to stop it.

Overmedication of foster children in Texas has been at issue for several years, and state officials have taken steps to reduce the use of psychotropics. A 2011 report by the U.S. Government Accountability Office found that 32 percent of Texas’ foster children were on psychotropic drugs, the second-highest rate in the nation — behind Massachusetts.

On Tuesday, TexasTribune.org reported that Texas’ rate has dropped from 42 percent in 2004 to 32 percent in 2012, even as the total number of children passing through foster care each year rose from 27,400 to 47,900. As of Dec. 31, 2012, officials said there were 15,760 children in the foster system. [....]

Andrea Calloway, who has represented 48 foster children during 11 years as a CASA volunteer in Denton County, recalled seeing a 3-year-old foster child who was “drooling on the couch,” because he had been prescribed behavior-altering and anxiety drugs soon after he went into foster care. “Foster homes are using psychotropic drugs to control these children. They can have more children in their home that way,” she said. “I have cried with kids who have been so messed up on this medication. … If they’re on the medication, their need is shown to be higher, and the providers get a higher reimbursement rate.” [....]

This is something that has to be attacked state by state.

I didn't check into what Massachusetts and the other "high" states are doing on it.

I do know that the Texas legislature, which has the power of the purse, works part time, and isn't fond of spending more money on anything; threats about federal Medicaid dollars might put a bee in their bonnet, and then publicized conferences that the Lt. Gov. attends might as well. But these wheels work slowly there....