Poison control centers have seen a sharp increase in the number of calls about teen misuse of attention-deficit drugs, suggesting "a rising problem with abuse of these medications," according to a new study out today.

The calls came from emergency room doctors, parents and school officials asking for advice for how to deal with apparent abuse of the increasingly common medications. The severity of the calls has increased over time and four deaths were reported in the study.

Teens, who many times use the drugs to get high, may not realize that there can be serious consequences to using what are, after all, prescription medications. Sales data of attention-deficit drugs suggest that abuse of the medications reflects an increased availability of the prescriptions, which have also been rising. The calls about ADHD medication rose 76 percent over an eight-year period, a pace outstripping calls for victims of substance abuse generally and teen substance abuse.

The study, in the journal Pediatrics, was done by Cincinnati Children's Hospital Medical Center researchers using data from 1998 to 2005.

Mark Stein, a psychiatry professor and ADHD expert at University of Illinois at Chicago, told the Associated Press that abuse typically involves crushing and snorting the pills, which speeds up the effects and can produce a buzz or sense of euphoria - along with dangerous side effects.

The study lacks information on whether abusers were teens with ADHD, but anecdotal evidence suggests many are not.