U.S. Attorney General Loretta Lynch, speaking to a group of high school students in Kentucky this week, said that marijuana is not a gateway drug, a prominent challenge to the most popular argument used by opponents of legalization.

On a speaking tour as part of President Obama’s Prescription Opioid Epidemic Awareness Week, the attorney general said prescription drug abuse, not pot, is the most important factor leading to hard drugs like heroin.

“In so many cases, it isn’t trafficking rings that introduce a person to opioids,” she said. “It’s the household medicine cabinet. Something you can have prescribed to you in good faith by a doctor. That’s the source.”

Lynch contended that marijuana’s role in the nation’s conversation about drug abuse and addiction has been overstated.

“It isn’t so much that marijuana is the step right before using prescription drugs or opioids—it is true that if you tend to experiment with a lot of things in life, you may be inclined to experiment with drugs, as well. But it’s not like we’re seeing that marijuana as a specific gateway,” said Lynch, who visited several places in Kentucky as part of some 250 activities planned for this awareness-raising week.

Kentucky is one of the states most seriously affected by the heroin and opioid epidemic in recent years, with drug overdose deaths increasing to 1000 a year, according to a report from the Office of Drug Control Policy.

Heroin and opioid overdoses in the United States account for 62 percent of all drug deaths. In states with the highest rates of fatal overdoses, opioids represent a disproportionately large share.

This alarming increase in overdose deaths, which skyrocketed 137 percent between 2000 and 2014, makes this week’s awareness campaign all the more critical.

The Obama administration is seeking $1.1 billion in new funding to fight opioid abuse and for treatment and care of addicts.

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