Hunter Walrath's parents were hopeful when a child psychiatrist prescribed Concerta for their 9-year-old son. A bright, highly verbal boy, Hunter has a laundry list of disabilities: he suffers from ADHD, faulty executive functioning, dyslexia and emotional problems that suggest Asperger's syndrome. His limited attention span and poor impulse control made him an outcast at school. But the Concerta, his parents say, had little effect. His doctor upped the dose, but still Hunter struggled. A few months later, when the doctor switched him to a cocktail of Ritalin and Strattera, the boy's behavior changed--but not for the better. He gained about 11 kilos, and his outbursts in class grew more intense. Back on Concerta, Hunter has improved and is starting a new school, but the Walraths are shaken. "Sometimes we wondered," says John Walrath. "Are the doctors making this up as they go along?"

The Walraths aren't alone on the medication merry-go-round. In the past decade, the number of psychoactive medications available to children has more than tripled. And increasing numbers of children are taking the drugs, too. In a U.S. study completed this February, New York University's Child Study Center found that 15 percent of parents with children between the ages of 5 and 18 reported giving their kids psycho-active medication daily.

When they work, psychoactive medications can be a godsend. But John Walrath wonders if Hunter's medical team "had a solid understanding" of his son's complex interplay of issues. "Those doctors' visits are fleeting," he says. Experts share the concern. In the Child Study Center survey, about 28 percent of parents who gave their kids drugs deemed the treatment "somewhat unhelpful" or "extremely unhelpful." "We find this worrisome," says Dr. Harold S. Koplewicz, director of the center, because it suggests that many kids may be on the wrong meds. With a growing wave of kids seeking treatment, "you have to wonder who is making the diagnosis," says Koplewicz. Most prescribing is done by a general practitioner or pediatrician, who may not have the time or expertise to do a thorough analysis.

The children who respond best to medication, experts say, are often the ones who fit snugly into widely recognized diagnostic categories like attention-deficit or obsessive-compulsive disorder. For quirkier kids, whose symptoms are hard to classify or who seem to have several disorders at once, pinpointing the right treatment can depend more on clinical judgment than on hard science. For those kids, says Dr. Richard Gorman, chairman of the American Academy of Pediatrics' Committee on Drugs, "there is a lot more ambiguity and a lot less data about what works." Medicine aimed at one set of symptoms can exacerbate other symptoms. Susannah Budington says that by the time her daughter Allison Stoll was 5, she'd already been diagnosed with ADHD but was prescribed Prozac to help manage her hypersensitivity, anxiety and an extreme phobia about bugs. In first grade, though, Allison's teacher complained that while the girl was bright and kind, she was disruptive: she couldn't sit still and blurted out answers. So Allison's psychiatrist added dexadrine to her menu of meds. The next day, Allison's mother noticed she was pulling out her eyebrows and eyelashes. "The dexadrine overrode the Prozac," says Budington, who discontinued the dexadrine.

Even with the right drugs, determining the right dosage isn't easy. Children metabolize some drugs faster than adults--so kilo for kilo, they often require more. But too much medication has dangers, of course. Dr. Anne McBride, a pediatric psychopharmacologist at the Payne Whitney clinic in New York, has seen young patients suffering from agitation, sedation, cognitive dulling, abnormal liver and kidney function and an impaired immune system. "They're toxic from too many drugs," she says. In those cases, McBride retains the medications that are appropriately prescribed and withdraws the questionable drugs one at a time. Another challenge: children can "outgrow" a drug's benefits. From third to sixth grade, Khristopher Royal used Ritalin to help him stay focused in class. But in sixth grade it simply stopped working. His doctor tried Ader-all, dexadrine and Wellbutrin. "Nothing worked," says his mother, Karran Harper Royal. "It was frustrating."

To help children get the most effective treatment, experts say that frontline physicians need better support. Pediatricians should be trained to treat simple cases and refer trickier kids to the specialists--child psychiatrists. Parents need to make sure that information flows between the child's prescribing physician and his teachers and therapist. And with a well-integrated program of behavioral therapy, says Dr. L. Eugene Arnold, an ADHD specialist at the Ohio State University Nisonger Center, "doctors can often reduce dosages of medication." Some can eliminate them altogether--giving parents and their quirky kids something to cheer about.