Early use of marijuana or cigarettes can significantly harm teenagers\u2019 results on English and mathematics exams, a new study finds. Marijuana\/cannabis and cigarettes are two of the three most widely consumed substances among teenagers in the U.S. Unfortunately, teens who consume these substances have substantially higher associated risks for addiction and other serious problems than their adult counterparts. In a study published in late 2014 in the journal Addiction, a team of British researchers assessed the impact that marijuana\/cannabis use and cigarette\/tobacco use before age 15 have on adolescents\u2019 academic achievement. The researchers concluded that early use of either of these substances can significantly harm a teen\u2019s performance in English and math. These results emphasize the need for teens who abuse marijuana to seek treatment for their addiction. Teens and Marijuana\/Cannabis Federal researchers from the National Institute on Drug Abuse use a University of Michigan-led project called Monitoring the Future to track nationwide trends in the use of alcohol, drugs and medications by American teens enrolled in the eighth grade, 10th grade and 12th grade. Long-term findings from this project indicate that the annual rate of marijuana use among U.S. high school seniors reached a historic peak (51 percent) in 1970. This is also the historic peak for teenagers in general, since 12th graders have a higher rate of marijuana intake than their younger counterparts. In 2013 (the last year with fully available figures), the annual rate of marijuana\/cannabis consumption among American high school seniors was 36.4 percent. This rate has not changed since 2010. Figures from 2013 indicate that 29.8 percent of U.S. 10th graders used marijuana at least once throughout the year. Among eighth graders, the annual rate of use was 12.7 percent. For both 10th graders and eighth graders, the annual rate of marijuana\/cannabis intake rose by a statistically significant amount over figures recorded for 2012. This finding may at least partially reflect the relatively recent increase in the social acceptability of marijuana consumption among U.S. adults. Teens and Cigarettes\/Tobacco Monitoring the Future also tracks nationwide trends in cigarette\/tobacco use among America\u2019s eighth, 10th and 12th graders. The historic peak for smoking among 12th graders (a monthly rate of 37 percent) occurred in 1997; by comparison, the monthly rate for 12th graders in 2013 was 16 percent. After increasing briefly in 2010, monthly smoking rates for eighth graders and 10th graders resumed a long-term decline in 2011, 2012 and 2013. In 2013, 9.1 percent of all 10th graders smoked cigarettes on a monthly basis. Among eighth graders, the monthly smoking rate was 4.5 percent. Projected trends show a likely continuation of the downward trend in cigarette\/tobacco use among all American teenagers. Impact on Educational Achievements In the study published in Addiction, researchers from several departments of the United Kingdom\u2019s University of Bristol used data from a long-term British project called the Avon Longitudinal Study of Parents and Children to explore the impact that consumption of marijuana\/cannabis or cigarettes\/tobacco during early adolescence has on the educational achievements of 15-year-olds. All told, the researchers included information gathered from 1,155 participants in this larger project. For each individual, they completed an assessment of all marijuana\/cannabis intake and cigarette\/tobacco intake before age 15. In addition, each participant took standardized tests designed to evaluate his or her English skills and math skills. The researchers concluded that the use of marijuana\/cannabis or cigarettes\/tobacco before the age of 15 is statistically linked to a significantly reduced level of performance on English tests and math tests. This finding holds true even when a range of other potential considerations are taken into account (including such things as gender, parental substance use, early teen alcohol use, any given teenager\u2019s socioeconomic standing, educational achievement in earlier stages of childhood and the presence of a diagnosable childhood condition called conduct disorder). When the researchers looked more closely at the variables involved, they determined that weekly intake of marijuana\/cannabis and daily intake of cigarettes\/tobacco are particularly associated with a decline in English- and math-related achievement among 15-year-olds. The study\u2019s authors found that two other considerations\u2014the presence of conduct disorder and the use of other types of substances before age 15\u2014have especially strong interactions with the risks posed by marijuana\/cannabis use and cigarette\/tobacco use. When these considerations are factored in, cigarette smoking is apparently associated with a larger decline in English and math skills than marijuana\/cannabis intake.