The dose makes the poison. - Paracelsus
Millennials are the strongest advocates for legalizing marijuana, but they may be paving their own pathway to a problematic educational future through their political support.
Fully 68 percent of millennials - those born after 1980 - want legal dope, according to a recent Pew survey. That's higher than any other generation. The impact of high-potency marijuana use on American educational achievement and even military readiness has been overlooked, if not dismissed. Yet there are serious reasons for concern.
A substantial increase in marijuana potency over the past 20 years is today producing much greater harm than before. Recent research has not only made associations with psychotic effects on susceptible individuals, but has also stressed associations with diminished IQ and cognitive performance with heavy use and even detected brain abnormalities in association with "casual" exposure.
The concentration of the intoxicant THC found in marijuana has climbed from roughly 3-4 percent in the 1980s to the 20-30 percent common in current commercial products, with newer forms of the drug (such as "shatter") reaching 70-80 percent THC, according to nationwide drug seizures. This increased potency ratchets up the damage to educational performance.
How widespread is marijuana use in this generation? According to Monitoring the Future, an annual school survey conducted for NIDA, in 2014, more than 44 percent of high school seniors reported "lifetime use" of marijuana, while more than 21 percent reported "Current use." These figures have held roughly steady for several years.
The National Institute on Drug Abuse reports that the use of marijuana, even mid-potency marijuana, affects educational performance because it "interferes with attention, motivation, memory, and learning," and that students who are regular users "tend to get lower grades and are more likely to drop out." NIDA concludes that youth using marijuana "may be functioning at a reduced intellectual level most or all of the time."
It looks increasingly likely that early marijuana use is a causal variable in declining intellectual capacity. Moreover, whatever correlations we find between exposure to THC and cognitive and behavioral deficiencies in youth will likely accelerate as marijuana is legalized.
There are new data that bear on the matter, as the Educational Testing Service reports on results from the Programme for International Assessment of Adult Competencies. When compared to their international counterparts in 24 advanced industrial nations, American students, specifically the millennial generation (between 16 and 34 years of age at time of assessment) continued to score near the bottom in literacy, math, and even the "ability to follow directions," despite having more years of schooling than their predecessors.
Education experts respond with reasonable explanations, such as America's diversity or income inequality, coupled with weakened schools.
But this time the "report card" from ETS is more complex. ETS notes that millennials look like America's "weakest generation" cognitively. And when ETS compared only the elite (90th percentile), native-born school performers across the international setting, Americans fared still worse. Intense marijuana use is found among U.S. youth in every social stratum. Correlation doesn't mean causation, but there is a correlation.
The impact may extend beyond schooling. Only 29 percent of youth of age for military service were deemed eligible for enlistment, with fully one-quarter failing the army's basic math and reading test. Further, daily use of marijuana by adolescents increased their risk of dropping out of high school by 66 percent, according to a recent Lancet analysis - and that dropout risk is even higher for the most socioeconomically disadvantaged, according to a report by the Brookings Institution's Hamilton Project.
And what of Colorado, where commercial marijuana exploded in January 2014? Nationally, daily use of marijuana among those 12 and older has already increased from 4.8 percent in 2002 to 8.1 percent by 2013. In 2011, Colorado's daily use rates were 35 percent higher than the national average.
But drug-related school disruption is climbing. According to a recent report from the Colorado Department of Education, the percentage of expulsions for drug violations exploded from 26.2 percent to 41.9 percent between 2008 and 2014, all prior to full commercialization.
Experts have even explored environmental factors, such as exposure to chemicals like phthalates, used in plastics and inked to IQ loss. A study involving zebra fish recently received attention in the Washington Post. Yet the Post has been silent regarding the environmental effects of THC.
Our argument is not that marijuana is the most important variable driving decline, though the evidence for a role is compelling. What we do argue is that anyone concerned with American schooling must account for this new threat.
John P. Walters and David W. Murray direct Hudson Institute's Center for Substance Abuse Policy Research. They served in the Office of National Drug Control Policy during the George W. Bush administration.