Current scientific evidence suggests that people who smoke cigarettes and nicotine-containing tobacco products have an unusually high chance of becoming consumers of marijuana. However, relatively few researchers have considered a reverse scenario in which the use of marijuana increases the odds of nicotine addiction. In a study published in September 2014 in the journal Substance Abuse, researchers from the New York University School of Medicine used a long-term project to help determine if teenagers who start smoking marijuana are unusually likely to develop nicotine addiction in early adulthood. Teens and Marijuana Roughly 14 percent of all 16- and 17-year-olds in the U.S. consume marijuana a minimum of once a month, according to recent figures compiled by the federal Substance Abuse and Mental Health Services Administration. In teenagers in the 12th grade, the rate of monthly marijuana intake rises to approximately 23 percent. Much smaller percentages of older and younger teenagers consume marijuana every day or almost every day. Broadly speaking, American teenagers are increasingly likely to view marijuana experimentation, occasional marijuana use and regular marijuana use as essentially harmless activities, concluded researchers from a federally funded survey project called Monitoring the Future. This finding directly contravenes the scientifically supported fact that teenagers who consume the drug are statistically far more likely to develop diagnosable symptoms of cannabis addiction than their older counterparts. Since attitude commonly translates into behavior, marijuana intake may continue to increase among U.S. adolescents in at least the short-term future. Nicotine Addiction Nicotine is one of the world\u2019s most addictive substances. Like the vast majority of other addictive substances, it produces its basic, mind-altering effects by triggering chemical changes in the brain\u2019s pleasure center that lead to an intense sensation known as euphoria. Repeated use of any euphoria-producing substance can eventually lead to a lasting change in baseline brain chemistry known as physical dependence. In the case of nicotine\/tobacco use, physical dependence is essentially synonymous with the onset of addiction. Young smokers can develop nicotine dependence\/addiction after consuming as few as 100 cigarettes (five full packs); this fact largely accounts for the secondary fact that most adults addicted to nicotine began smoking while in adolescence. The American Psychiatric Association categorizes nicotine addiction as part of a larger condition called tobacco use disorder; most of the people in the U.S. and other countries who regularly smoke cigarettes qualify for a diagnosis of this condition. Marijuana Use and Nicotine Addiction In the study published in Substance Abuse, the New York University researchers used information gathered periodically from 816 individuals during adolescence and early adulthood to help determine if teen marijuana use is associated with heightened risks for nicotine addiction among young adults. The researchers collected this information at five points in time separated by five-year intervals. At the beginning of the study, the average age of the participants was 14; at the time of the last data-gathering point, the participants had an average age of 32. The researchers looked at the long-term effects of five patterns of marijuana consumption in adolescence: lack of intake, a low level of intake, a moderate and steady level of intake, a transition from a moderate to a heavy level of intake and an initially heavy level of intake. After examining the available data, the researchers concluded that those individuals who consume little or no marijuana at the age of 14 do not have increased odds of developing nicotine addiction at some point during their 20s or early 30s. However, they also concluded that those individuals who consume moderate, moderate-to-heavy and heavy amounts of the drug at age 14 do have significantly increased odds of developing nicotine addiction at some point during young adulthood. The study\u2019s authors believe their findings underscore the fact that marijuana use early in life can increase the risks for problematic nicotine\/tobacco use later in life, just like nicotine\/tobacco use in early life can increase the risks for problematic marijuana use later in life. In line with this conclusion, they stress the need to consider the impact that different patterns of early marijuana intake can have on the health of young adults. The authors also believe that anti-marijuana campaigns targeted at young people should include messages targeted at the potentially damaging use of cigarettes.