"More schools and students are captured in the HYS [Washington Healthy Youth Survey] than MTF [Monitoring The Future Survey] (Table). The MTF included fewer low–socioeconomic status and nonwhite youth in the prelegalization vs postlegalization period.

"The number of juvenile marijuana arrests decreased 16%, from 3,168 in 2012 to 2,655 in 2017. The rate of juvenile marijuana arrests per 100,000 decreased from 583 in 2012 to 453 in 2017 (‐22%).

"The number of White juvenile arrests decreased from 2,146 in 2012 to 1,703 in 2017 (‐21%).

"The number of Hispanic juvenile arrests decreased from 767 in 2012 to 733 in 2017 (‐4%).

"The number of Black juvenile arrests decreased from 202 in 2012 to 172 in 2017 (‐15%)."

"Data on youth marijuana use was available from two sources. The Healthy Kids Colorado Survey (HKCS), with 47,146 high school and 6,704 middle school students responding in 2017, and the National Survey on Drug Use and Health (NSDUH), with about 512 respondents in 2015/16.

"In summary, current evidence does not support the hypothesis that MML passage is associated with increased marijuana use prevalence among adolescents in states that have passed such laws up until 2014. Based on this evidence, we recommend several steps to advance the understanding of current and future marijuana policy effects. First, continued exploration of the effects of these state policies on different measures of use among adolescents is warranted.

"The perceived availability of cigarettes continued a long-term decline in 8th and 10th grade to historic low levels, with a significant decline in 10th grade. (Availability of cigarettes in 12th grade was first asked this year, so trend data are not yet available). After holding fairly steady at very high levels for some years, perceived availability reported by 8th and 10th graders began to decline modestly after 1996, very likely as a result of increased enforcement of laws prohibiting sale to minors under the Synar Amendment and FDA regulations.

"Although availability of alcohol among 12th grade students is near its lowest level recorded since first measured in 1999, at 86% it is still very high.

"Marijuana has been the most consistently available illicit drug and has shown only small variations over the years (see Figure 9-5a). What is most noteworthy is how little change has occurred in the proportion of 12th graders who say that marijuana is fairly or very easy to get. By this measure, marijuana has been readily available to the great majority of American 12th graders (from 80% to 90%) since 1975.

"Inhalants rank second among the illicit drugs in lifetime prevalence for 8th graders (8.9%) and third for 10th graders (6.1%); but they rank seventh for 12th graders (4.9%). Inhalants also rank second-highest in 30-day prevalence among the illicit drugs for 8th (2.1%) and third (1.1%) among 10th graders, but they rank much lower for 12th graders (0.8%). Note that the youngest respondents report the highest levels of use; this is the only class of drugs for which current use declines with age during adolescence.³"

"Annual marijuana prevalence peaked among 12th graders in 1979 at 51%, following a rise that began during the 1960s. Then use declined fairly steadily for 13 years, bottoming at 22% in 1992—a decline of more than half. The 1990s, however, saw a resurgence of use. After a considerable increase (one that actually began among 8th graders a year earlier than among 10th and 12th graders), annual prevalence rates peaked in 1996 at 8th grade and in 1997 at 10th and 12th grades. After these peak years, use declined among all three grades through 2007 or 2008.

"Teen users are at significantly higher risk of developing an addictive disorder compared to adults, and the earlier they began using, the higher their risk. Nine out of 10 people who meet the clinical criteria for substance use disorders involving nicotine, alcohol or other drugs began smoking, drinking or using other drugs before they turned 18. People who begin using any addictive substance before age 15 are six and a half times as likely to develop a substance use disorder as those who delay use until age 21 or older (28.1 percent vs. 4.3 percent)."