College students who use prescription stimulants meant to control attention-deficit disorder as study aids prefer the slow-release drug Adderall to Ritalin, researchers from Northeastern University report.

Students are three times more likely to take Adderall than Ritalin; the drugs are popular because they increase concentration and are seen as a way to boost academic achievement. Adderall is an amphetamine-dextroamphetamine product, while Ritalin's active ingredient is methylphenidate.

Researchers found that far more college students took the drugs to improve their schoolwork than to get high. Most ingested the pills orally, but 40 percent said they had snorted the stimulants, reported lead researcher Christian Teter, a pharmacy professor at Northeastern.

Misuse of drugs like Adderall and Ritalin varied by race; white students were the most likely to use the drugs to study or get high, followed by Asians, Hispanics, and blacks. Most students only began using the drugs in college.

Researchers speculated that Adderall is more popular than Ritalin because it produces a steadier, longer-lasting effect and also is more commonly prescribed, and thus more available.

The study, "Illicit Use of Specific Prescription Stimulants among College Students: Prevalence, Motives, and Routes of Administration," appears in the October 2006 issue of the journal Pharmacotherapy.