Decades of public health campaigns designed to convince teens not to smoke appear to be working \u2014 at least in a sense. Young people are increasingly turning away from tobacco, a Penn State study has found, but more are lighting up with marijuana. It was an unexpected finding for the researchers, one that has them planning more study to see if the legalization of marijuana in certain parts of the country is playing a role in the increase. Stephanie Lanza, scientific director of the university\u2019s Methodology Center and a professor of biobehavioral health, said in a Penn State news release that the research proves that anti-smoking campaigns appear to be having their intended effect. "However, we were surprised to find the very clear message that kids are choosing marijuana over cigarettes.\u201d Black Teens Catch Up to White Teens in Pot Use In reaching their conclusions, the researchers analyzed data gathered from nearly 600,000 high school students from 1976 to 2013 as part of the Monitoring the Future study, an ongoing survey project which annually asks students to share information about their values, attitudes and behaviors, including substance use. The researchers focused on student answers about past-month use of cigarettes, marijuana and alcohol. What they found was that cigarette use has declined relatively consistently over the past few decades, but marijuana use is up from its low in the 1990s, particularly among black teens. It breaks down this way: \tIn the 1990s, 37% of white teens smoked cigarettes and 20% used marijuana. In 2013, 19% smoked cigarettes and 22% used marijuana. That\u2019s a decrease of almost 49% in smoking and an increase of 10% in marijuana use among white teens in the last couple of decades. \tBy contrast, 12% of black teens smoked cigarettes in the 1990s, and 14% used marijuana. In 2013, 10% smoked cigarettes and 25% smoked marijuana. That\u2019s an almost 17% decrease in cigarette smoking and an almost 79% increase in marijuana use among black teens. It remains unclear why youths appear to be trading tobacco for marijuana and why black teens in particular went from being equally likely to use marijuana and cigarettes in the 1990s to a surge in marijuana use. Relaxing attitudes toward marijuana may offer at least part of the explanation. Four states and Washington, D.C. have now legalized recreational marijuana use and more are set to follow their lead, and a 2015 survey by the Pew Research Center shows the majority of the country now supports legalization of the drug. Recreational use of marijuana is legal, however, only for those 21 and up. The researchers also found that marijuana and other substance use often go hand in hand. For example, teens who smoked cigarettes were more likely to be pot smokers \u2014 and vice versa. And teens who drank to excess also tended to use marijuana \u2014 and vice versa. Teen Drinking Declines Overall Among other study results: Teen drinking and teen binge drinking is down dramatically for both black and white teens in the 2010s compared to the 1970s, but white teens remain the biggest drinkers and use alcohol more than any other substance. \tIn the 2010s, 44% of white teens said they had a drink in the past month, compared to 29% of black teens. \tTeen drinking is down almost 41% for both white and black teens since the 1970s. \t26% of white teens reported binge drinking in the 2010s compared to 12% of black teens. \tBinge drinking is down overall by about 38%. The study was published in July 2015 in the Journal of Adolescent Health.