Spinning the marijuana story

If you didn’t know any better, you’d think marijuana is making a big comeback among teenagers.

Study shows pot more popular among teenagers, the headline on the Associated Press story (on the MPR Web site) says today. The story claims “smoking marijuana is becoming even more popular among U.S. teens.” It cites a news conference held by the National Institutes of Health, based on research from the University of Michigan.

But is marijuana use really on the upswing? It depends on whom you listen to.

According to the NIH news release, “no.”

Marijuana use across the three grades has shown a consistent downward trend since the mid- 1990s, however, the decline has stalled, with rates at the same level as five years ago. In the 2009 survey, reported past year marijuana use was about the same as the previous year: 32.8 percent of 12th graders, 26.7 percent of 10th graders, and 11.8 percent of eighth graders. However, marijuana use is still down significantly from its peak in the mid-late 1990s.

But the University of Michigan news release suggests otherwise:

Marijuana use among American adolescents has increased gradually over the past two years (three years among 12th-graders) following years of declining use, according to the latest Monitoring the Future study, which has tracked drug use among U.S. teens since 1975.

Two agencies, same data, two different headlines. Which is it?

It’s all in how you characterize things. The “increase” cited by the Michigan researchers was only for two or three years, and it averaged a 2-3 percent increase over that time. That may be statistically insignificant, so the NIH compared the current results to five years ago and found a less troubling trend.

Both, however, acknowledge that marijuana use by teenagers is well off the highs — so to speak — of the ’90s.

Keep in mind that these sorts of studies can be ‘spun” to accomplish political goals. Take the AP story, for example:

“The increase of teens smoking pot is partly because the national debate over medical use of marijuana can make the drugs seem safer to teenagers, researchers said.”

Researchers said that? What researchers? The University of Michigan news release mentions nothing about the effects of the debate over medical marijuana. And the data it provides indicates no such research took place.

Today, Dr. Lloyd Johnston, the principal researcher for the study, told me in an e-mail:

The issue you mention came up in answer to a question at today’s press conference. We know that there has been a decline in the degree to which young people see marijuana use as involving a risk to the user, what we have called “perceived risk”. I was asked why I thought the change in this belief has taken place. I said that one possible explanation is that the widespread debate about the desirability of medical marijuana use may well have led some teens to think that is is not as dangerous as their predecessors did, since it is now being portrayed as a medicine. It’s a conjecture on my part.

That’s something to keep in mind if debate over the issue resurfaces when the Minnesota Legislature resumes its work in February. Medical marijuana has been an issue in the last several sessions and last spring Gov. Tim Pawlenty vetoed a measure that would have allowed it in Minnesota.

The other thing to keep in mind is we’re not necessarily talking about the same kids here. Since the surveys don’t appear to track the same kids from year to year (I couldn’t find the actual methodology), we don’t really know whether the individual opinions and attitudes toward pot have changed. We only know that the kids surveyed last year may have had different attitudes than the kids who were surveyed this year. That doesn’t mean that individual attitudes have shifted.

  • michael

    i really like your cross referencing. great reporting MPR

  • Justin

    There is a reporter who knows how to dig deep and go beyond the soundbite! Good job.