New research suggests that the sleep-disorder drug Modafinil may carry a higher risk of abuse or addiction than scientists previously believed, USA Today reported March 17.

Researchers examined PET scans of 10 healthy men who were given either 200 milligrams of Modafinil (the recommended daily dose for treating sleep disorders), or double that dose. Both groups saw dopamine levels increase to that achieved by taking methylphenidate (a drug used to treat attention deficit hyperactivity disorder), but not as high as dopamine levels triggered by amphetamine use.

Drugs that increase dopamine levels are believed to have potential for abuse.

Some individuals take modafinil to help them stay awake (as a study aid, for example) rather than to treat sleep disorders, the researchers said. Lead author Nora Volkow, who is also director of the National Institute on Drug Abuse, said modafinil and other “smart drugs” may also have adverse effects like brief psychotic episodes in addition to having the potential for addiction.

The study was published March 18, 2009 in the Journal of the American Medical Association.