In the final months of Rebecca Riley's life, a school nurse said the little girl was so weak she was like a "floppy doll."

The preschool principal had to help Rebecca off the bus because the 4-year-old was shaking so badly.

And a pharmacist complained that Rebecca's mother kept coming up with excuses for why her daughter needed more and more medication.

None of their concerns was enough to save Rebecca.

Rebecca - who had been diagnosed with attention deficit hyperactivity and bipolar disorder, or what used to be called manic depression - died Dec. 13 of an overdose of prescribed drugs, and her parents have been arrested on murder charges, accused of intentionally overmedicating their daughter to keep her quiet and out of their hair.

Documents reviewed

Interviews and a review of court documents by The Associated Press make it clear that many of those who were supposed to protect Rebecca - teachers, social workers, other professionals - suspected something was wrong, but never went quite far enough.

But the tragic case is more than a story about one child. It raises troubling, larger questions about the state of child psychiatry, namely: Can children as young as Rebecca be accurately diagnosed with mental illnesses? Are rambunctious youngsters being medicated for their parents' convenience? And should children so young be prescribed powerful psychotropic drugs meant for adults?

Dispensing drugs to children diagnosed with mood or behavior problems is "the easiest thing to do, but it's not always the best thing to do," said Dr. Jon McClellan, medical director of the Child Study and Treatment Center in Lakewood. "At some level, I would hope that you'd also be teaching kids ways to control their behavior."

According to the medical examiner, Rebecca died of a combination of clonidine, a blood pressure medication Rebecca had been prescribed for ADHD; Depakote, an antiseizure and mood-stabilizing drug prescribed for the little girl's bipolar disorder; a cough suppressant; and an antihistamine. The amount of clonidine alone in Rebecca's system was enough to be fatal, the medical examiner said.

FDA approved

The two brand-name prescription drugs are approved by the Food and Drug Administration for use in adults only, though doctors can legally prescribe them to youngsters, and do so frequently.

Rebecca's parents, Michael and Carolyn Riley, say they were only following doctor's orders. Rebecca, they told police, had been diagnosed when she was just 2 1/2 , and Rebecca's psychiatrist prescribed the same potent drugs that had been prescribed for her older brother and sister when she diagnosed them with the same illnesses several years earlier.

But Rebecca's teachers, the school nurse and her therapist all told police they never saw behavior in Rebecca that fit her diagnoses, such as aggression, sharp mood swings or hyperactivity.

The case

Prosecutors say the Rileys intentionally tried to quiet their daughter with high doses of clonidine. Relatives told police the Rileys called clonidine the "happy medicine" and the "sleep medicine."

Through their attorneys, Michael Riley, 34, and Carolyn Riley, 32, have accused Rebecca's psychiatrist, Dr. Kayoko Kifuji, of over-prescribing medication.

Kifuji did not return calls for comment and declined to be interviewed. But Kifuji has vehemently denied any role in Rebecca's death. She has agreed to a suspension of her license while the state's medical board investigated.

Tufts-New England Medical Center, where Kifuji worked, issued a statement supporting Kifuji, saying her care of Rebecca "was appropriate and within responsible professional standards."

In the months leading up to Rebecca's death, others noticed there was something wrong.

Teachers and staff members at the Johnson Early Childhood Center in Weymouth, about 20 miles south of Boston, say they called Rebecca's mother repeatedly to tell her that Rebecca was "out of it," but her mother said the girl was tired because she wasn't sleeping well.

"They looked like little robots. They looked very lethargic," Phyllis Lipton said. "I said, 'Wow, they don't look right,' but who knew?"