‘Non-Addictive’ Modafinil Might be Addictive After All
Modafinil was developed in 1998 to treat narcolepsy and sleep disorders, but has since been used to treat fatigue, Parkinson’s disease, and depression. It has also become a popular stimulant used to stay awake and become more alert and focused. When modafinil was first approved by the FDA, it didn’t boost dopamine levels like amphetamines do; however, subsequent research on animals suggests that it does.
“It was believed that modafinil won’t have a prominent dopaminergic effect and the likelihood of addiction is very low,” said Nora Volkow, co-author of the study and director of the National Institute on Drug Abuse. “But the potential for abuse and addiction is likely to be there.”
The use of modafinil has been increasing—an informal survey in the journal Nature found that approximately one in ten researches have used modafinil, and non-prescription use seems to be increasing. “At the moment we start seeing addictive properties of a substance that was thought to be non-addicting, red flags go up,” said Judy Illes, a neuroethicist at the University of British Columbia. “We’re no longer talking about a substance that meets safety standards.”
In Volkow’s study, therapeutic doses of modafinil were given to ten men, who were then injected with small doses of cocaine labeled with short-lived radioactive isotopes. Using imaging technology, the researchers watched the cocaine enter the brain’s pleasure centers, where it would normally bind with dopamine receptors. However, instead of binding, the cocaine continued to circulate, which, according to Volkow, is a sign that the modafinil had already blocked the receptors. When dopamine receptors are blocked, circulating levels of dopamine increase.
The results aren’t conclusive enough to declare that the drug is indeed addictive, Volkow said, explaining that other chemical reactions could counteract the dopamine effects. She also said that medical literature contains isolated reports of abuse but none of addiction—though that may be because modafinil is relatively new and researchers hadn’t until now checked to see if people are addicted to it. She thinks that drug-abuse researchers should continue to study modafinil’s effects, and that doctors should monitor modafinil patients for signs of dependence.