A study of government surveys released this week shows some shocking statistics on marijuana use. Almost 10 percent — more than 22 million — of U.S. adults use marijuana.

Researchers say of those 22 million, 1 in 3 had signs of marijuana dependence or abuse. The results come from a comparison of health surveys from 2001-02 and 2012-13 sponsored by the National Institute on Alcohol Abuse and Alcoholism. Almost 80,000 adults aged 18 and older participated in face-to-face interviews about various health-related behaviors. Results were published Wednesday in the journal JAMA Psychiatry.

Participants were asked if they had used marijuana in the past year, and about signs of problematic use. Those include trying but unable to reduce heavy use, and continued use despite knowing it may be damaging health or causing depression or anxiety — problems affecting about 6.8 million adults, the latest survey suggests.

Use increased among all ages but was most common in adults aged 18-29.

What’s just as striking is that the results seem to show some “people can use marijuana without harms, but there are risks,” the report’s lead author wrote.

Teen marijuana use is also higher. About 23 percent of high school students had used the drug in the past month in 2013.

While adults may can handle their weed without trouble, can teens and younger children?  Most of us would agree that marijuana use among teens is unacceptable and dangerous. But when states legalize recreational use — or significantly reduce penalties for possession — it sends the signal to teens that marijuana is safe.

As more adults use marijuana, more teenagers and children will naturally have access to it — the same way many teens had access to dad’s liquor cabinet in the past. That’s a dangerous unintended consequence that deserves some attention.