Adams and Health and Human Services Secretary Alex Azar said they support additional research on the impacts of marijuana. But Adams -- known as "the nation's doctor" -- said the latest research is clear that marijuana is particularly harmful to developing brains and can be passed along to babies in utero or through breastmilk.
At a news conference, Adams told reporters that he was deeply concerned about what he called the "rapid normalization" of the drug and a false perception among young people that because it's now legal in some states that it must be safe.
"Not enough people known that today's marijuana is far more potent than in days past," the surgeon general said.
"This ain't your mother's marijuana," he added.
"Almost no activity is entirely without risk, which is exactly why marijuana should be legalized and regulated for adult use," said Erik Altieri, the executive director of the National Organization for the Reform of Marijuana Laws. "While marijuana still remains objectively less harmful to the consumer than currently legal alcohol, tobacco, and many pharmaceuticals it should still be consumed responsibly."
He added: "Our current model of prohibition represents the utter lack of control over any aspect of marijuana or the marijuana market. If he truly has concerns, the Surgeon General's time would be better spent advocating for a structure for regulation under which we can educate Americans about the actual harms and benefits of cannabis through public education campaigns and product labeling, instead of his current fear-mongering."
HHS chief Azar said the federal government will launch a public awareness campaign, and that President Donald Trump would be donating a portion of his salary to those efforts.
Azar said the government doesn't know everything about the drug's impact, but he insisted that the best science shows that it's addictive and damaging.
“State laws on marijuana has changed, but the science has not. And federal law has not," he said.
President of the group Smart Approaches to Marijuana (SAM), Dr. Kevin Sabet, issued a statement supporting the latest warning, saying that "the significance of today’s marijuana advisory cannot be overstated," comparing it to "the famous advisory on tobacco in 1964."
"Big Marijuana and its promoters have consistently pushed blatant falsehoods and misinformation to suggest marijuana is safe, despite the large and growing of evidence to the contrary. Administration officials should be applauded for finally shining a light on the harms of today’s high potent marijuana," Sabet said.
Last year, the surgeon general issued a similar strong warning against e-cigarette use by young people, called it "unsafe" in any form and termed vaping an "epidemic."
The American Academy of Pediatrics has long warned against the use of marijuana by young people. And the group has said no amount of marijuana has been proven safe to use during pregnancy or while breastfeeding.
Marijuana can have varying levels of potency depending on its THC level (delta-9-tetrahydrocannabinol). According to HHS, the THC concentration in commonly cultivated marijuana plants increased three-fold between 1995 and 2014.
HHS said that, according to research pregnant, women use marijuana more than any other illicit drug.