“We can’t have states legalizing medical marijuana! What about the children? What kind of message do we want to send to the children? If you legalize pot, more of that deadly drug will fall into the hands of our teenagers!”

Nonsense.

SACRAMENTO — Bucking dire predictions by anti-drug warriors, the 10 states that approved medical marijuana laws over the last decade have experienced sharp declines in cannabis use among teenagers, according to a new study by a marijuana advocacy group.

California has seen usage among ninth-graders drop 47% since 1996, the year the state became the nation’s first to legalize medical marijuana. Over the same period, the nation as a whole experienced a 43% decline among eighth-graders.

That data “strongly suggests” that approval of medical marijuana has not increased recreational use of cannabis among adolescents, Earleywine and O’Keefe concluded. And the decline in many of the states with medical marijuana laws is “slightly more favorable” than trends nationwide, they said.

California, Washington and Colorado have all experienced greater drops in marijuana usage than have occurred nationwide. Only three states with medical marijuana laws — Maine, Oregon and Nevada — have lagged behind the national drop in teen marijuana use, the report said.

“If medical marijuana laws send the wrong message to children,” the authors said, widespread attention to the debate “would be expected to produce a nationwide increase in marijuana use, the largest increase in those states enacting medical marijuana laws. But just the opposite has occurred.”

“Perhaps medical marijuana laws send a very different message,” they wrote. Teens may increasingly consider pot “a treatment for serious illness, not a toy, and requires cautious and careful handling.”

The most extensive available data was in California, where a survey of about 6,000 students every two years showed that pot use among teens was climbing before passage of the 1996 medical marijuana law. For all grades, marijuana use dropped significantly between early 1996 and 2004, with the biggest downward shift among ninth-graders.

Between 1996 and 2004, the number of high school freshmen in the state who reported using pot in the last 30 days dropped 47%, while the number of freshmen who had tried cannabis at least once dropped 35%.

The prohibitionists counter by saying that marijuana use has declined nationwide thanks to the anti-marijuana ads they’ve been running (you know the ones: where the kids smoking pot find dad’s loaded gun, or where the stoners at the drive-thru run over a little girl on her bike… you know, realistic portrayals of everyday marijuana usage… NOT!), which would have been even more effective if the medical marijuana issue wasn’t “clouding” their message.

Bah! Here’s a thought for you, and anyone who’s ever been, known, or parented a teenager, you tell me how sound the analysis is. Kids love to do stuff to appear “adult” Kids love to do the stuff you tell them not to do. When pot is seen in movies and culture as an “adult” thing, kids want to do it. When pot is seen in anti-drug ads as “forbidden fruit”, they want to do it more.

But when marijuana is demystified and becomes grandma’s glaucoma medicine, it is no longer seen as a sexy, recreational, rite-of-passage experience. When kids are told the truth about weed — that it’s not going to kill you, ruin your life (unless you’re arrested), or cause major health problems — it loses some of its bad-boy allure.

More detail from the study’s executive summary follows after the jump.

• In California — which has the longest-term, most detailed data available — the number of ninth graders reporting marijuana use in the last 30 days declined by 47% from 1996 (when the state’s medical marijuana law passed) to 2004. An analysis commissioned by the California Department of Alcohol and Drug Programs found “no evidence supporting that the passage of Proposition 215 increased marijuana use during this period.”
• In Washington state, sixth graders’ current and lifetime marijuana use has dropped by at least 50% since the 1998 enactment of the state’s medical marijuana law. All other surveyed grade levels have seen both lifetime and current marijuana use drop by between 25% and 50%.
• In Hawaii, youth marijuana use has decreased among all surveyed grade levels — by as much as 38% — since the 2000 passage of the state’s medical marijuana law.
• Data from Maine suggest a modest decline since the 1999 passage of its law. Data from Nevada (whose law was passed in 2000) and Alaska (whose law was passed in 1998) show overall decreases in marijuana use, with a modest increase in a few individual grade levels. Data from Oregon (whose law passed in 1998) suggest modest declines in marijuana use among the two grades surveyed in 2004, a slight decrease in lifetime marijuana use among high schoolers, and a tiny increase in current marijuana use among high schoolers. Colorado (whose law passed in 2000) is the only state without an in-depth statewide survey, but the limited data available suggest modest declines in Colorado teens’ marijuana usage as well.
• Vermont and Montana, whose medical marijuana laws were enacted in 2004, have not yet produced statistically valid data covering the period since their laws were passed.
• Nationwide, teenage marijuana use has decreased in the nine years since California enacted the country’s first effective medical marijuana law. Overall, the trends in states with medical marijuana laws are slightly more favorable than the trends nationwide. California, Washington, and Colorado have all seen much greater drops in marijuana usage than have occurred nationwide. Overall, Alaska’s and Hawaii’s trends are also more favorable than nationwide trends, though some individual measures are less favorable. Trends from Maine, Oregon, and Nevada are slightly less favorable than nationwide trends, although use is still down.

Details on California, where the best survey data can be found:

The biennial California Student Survey (CSS), conducted by the California attorney general’s office, provides some of the most detailed information on teen drug use trends in any single state. It measures three grade levels’ weekly, monthly, and past-six-month marijuana use. The pre-Prop. 215 survey (1995-1996) was based on the responses of 5,775 students, while the most recent survey (2003-2004) was based on responses from about 6,315 students. In the years prior to the 1996 passage of Prop. 215, the CSS charted steady increases in marijuana use by California teenagers in all surveyed grades — seventh, ninth, and eleventh graders. That period of increase ended in 1996, with CSS data showing a clear, swift downward trend since Prop. 215 passed on November 5, 1996. For all grades, marijuana use dropped markedly by every measure between early 1996 and 2004. Among ninth graders, current use dropped by nearly half.

• 7th grade weekly: 37% decrease since late 1995/early 1996 (from 1.9% to 1.2%)
• 9th grade weekly: 50% decrease since late 1995/early 1996 (from 12.3% to 6.2%)
• 11th grade weekly: 36% decrease since late 1995/early 1996 (from 16.5% to 10.6%)
• 7th grade past 30 days: 37% decrease since late 1995/early 1996 (from 6.2% to 3.9%)
• 9th grade past 30 days: 47% decrease since late 1995/ early 1996 (from 23.6% to 12.4%)
• 11th grade past 30 days: 24% decrease since late 1995/ early 1996 (from 25.9% to 19.8%)
• 7th grade past six months: 44% decrease since late 1995/early 1996 (from 10.9% to 6.1%)
• 9th grade past six months: 45% decrease since late 1995/early 1996 (from 34.2% to 18.8%)
• 11th grade past six months: 29% decrease since late 1995/early 1996 (from 42.8% to 30.5%)
• 7th grade lifetime: 24% decrease since late 1995/early 1996 (from 10.9% to 8.3%)
• 9th grade lifetime: 35% decrease since late 1995/early 1996 (from 35.0% to 22.8%)
• 11th grade lifetime: 17% decrease since late 1995/early 1996 (from 46.9% to 38.7%)

California teens’ marijuana use rates since 1995 compare favorably to national numbers. Of the national surveys measuring teen marijuana use, only the YRBS surveyed some of the same grades as the CSS — ninth and eleventh. While the YRBS found decreases in youth marijuana use, the decreases were not nearly as sharp as California’s decreases. The YRBS estimates a 9% decrease in ninth graders’ lifetime marijuana use since 1995. In the same time period, lifetime marijuana use has decreased by 35% among California ninth graders. Ninth graders’ past 30-day marijuana usage has decreased by 47% in California, but by only 11% nationwide.

California saw so much concern about Prop. 215’s possible effect on youth marijuana use that the 1997-98 version of the CSS included an added set of questions intended to gauge the measure’s impact. Researchers from the educational research firm WestEd, located in Los Alamitos, California, analyzed the data. Their report — never formally published but considered public information by the California Department of Alcohol and Drug Programs — was prepared in September 1999.

The researchers found that “students were well aware of the proposition and its meaning,” with 63.5% of ninth graders and 74% of eleventh graders saying they had either read about the measure or heard adults talk about it in person or in the media. Regarding the impact of Prop. 215 on marijuana use, they concluded:

Use of marijuana by youth, which had been on an upward trend since the early 1990s at all three grade levels, did not intensify as predicted by the “wrong message” theory. Instead, it leveled off between 1995-96 and the current (1997-98) survey. There is no evidence supporting that the passage of Proposition 215 increased marijuana use during this period [emphasis added].

The researchers did sound a note of caution about “the softening of perceived harm,” writing, “Marijuana use should be followed over the next several years to assess the impact of Proposition 215 on the marijuana use in California’s youth.” In this context, the steep declines in use recorded by later surveys are noteworthy.