UM Study Finds Teen Cigarette, Pot Use Rising
The very substantial decrease in teen smoking that began in the mid-1990s has come to a halt among younger teens in the United States, and some evidence of a possible increase in their smoking was observed this year, according to the University of Michigan's Monitoring the Future study.
The study also found marijuana use continues to rise, while use of ecstasy appears to be making a comeback, following a decline in belief that it is dangerous. Heavy drinking, however, continues its long term decline among teens.
The Monitoring the Future study, which has been tracking teen smoking in the United States for the past 36 years, reports that past 30-day smoking among 8th graders increased from 6.5 percent in 2009 to 7.1 percent in 2010; among 10th graders it rose from 13.1 to 13.6 percent.
These estimates come from the study's national surveys of some 46,000 students in nearly 400 secondary schools each year. The study is directed by a team of research professors at UM's Institute for Social Research, and since its inception has been funded through a series of research grants from the National Institute on Drug Abuse -- one of the National Institutes of Health.
According to Lloyd Johnston, the study's principal investigator, smoking behavior among younger teens is particularly important because it is predictive of their smoking behavior as they become older teens and young adults.
"Smoking is a habit that tends to stay with people for a long time, leading to ongoing differences between different graduating classes of students that persist into adulthood," he said. "Scientists call it a cohort effect, and it occurs largely because cigarette smoking is so addictive."
Peak smoking levels among teens were reached around 1996 among 8th and 10th graders and in 1997 among 12th graders. In the five or six years immediately following those peak levels, smoking among teens fell sharply. This likely was due in large part to increased public attention to the issue as well as to sharply rising prices, caused in part by new state sales taxes on cigarettes.
Negative publicity about the tobacco industry increased dramatically during that period, while the 1998 Master Settlement Agreement between states' attorneys general and the major cigarette companies generated its own consequences. These included the industry raising cigarette prices considerably to help them cover the costs of the settlement; reducing the nature and amount of adverting reaching youth, including ending the Joe Camel ad campaign; and funding a national anti-smoking advertising campaign aimed at youth.
After 2002 (or 2003 in the case of the 12th graders) the decline in teen smoking slowed considerably as funding was cut back substantially for national and state anti-smoking campaigns and as less public attention was paid to the issue generally. "In other words," Johnston concludes, "some of the factors that contributed to the earlier decline, by helping to shape young people's views of smoking were and are no longer occurring." Cigarette prices were not rising as dramatically, either, though they did continue to rise.
The proportion of students seeing a great risk associated with being a smoker leveled off during the past several years, according to the study's results, as has the proportion of teens saying that they disapprove of smoking or attach negative connotations to it.
Only high school seniors showed some modest further decline in smoking in 2010. None of their declines in use this year was significant: 30-day prevalence fell by 0.9 percentage points to 19.2 percent, and current daily smoking fell by 0.4 percentage points to 10.7 percent. As the study has previously demonstrated, cigarette smoking is generally characterized by cohort effects. Therefore, the investigators predict that the downturn in smoking among 12th graders will come to a halt within a year or two, because it already has ended among the younger cohorts who soon will be entering 12th grade.
All three grades now have rates of smoking that are far below their peak rates in 1996 or 1997.
"These are extremely important changes that will carry very substantial consequences for the health and longevity of this generation of young Americans," states Johnston. "But there are still significant proportions of teens putting themselves at risk for a host of serious diseases and a premature death because they are taking up cigarette smoking."
The use of smokeless tobacco (which includes snuff, plug, dipping tobacco, chewing tobacco, and more recently "snus") also is assessed in the study. ("Snus" is pronounced snoose, and rhymes with goose.) From the mid-1990s to the early 2000s, there was a substantial decline in smokeless tobacco use among teens but the declines have not continued. In fact, significant increases have occurred over the past several years in all three grades. While so far modest in size, these changes show a clear rebound in use. Thirty-day prevalence of smokeless tobacco use in 2010 is 4.1 percent, 7.5 percent, and 8.5 percent, among 8th, 10th, and 12th graders, respectively. The rates are considerably higher for boys -- 6.3 percent, 13.0 percent, and 15.7 percent.
Perceived risk appears to have played an important role in the decline of smokeless tobacco use, as was true for cigarettes. In all three grades, perceived risk for smokeless tobacco rose fairly steadily from 1995 through 2004 before leveling. However, there has not been a great deal of fall-off in these measures since 2004, suggesting that other factors may be leading to the recent increases in use -- quite possibly increased advertising of these products and a proliferation of types of smokeless tobacco available.
Two of the latest developments to raise public health concern are the smoking of tobacco by using hookah water pipes and the smoking of small cigars. Questions about these forms of tobacco use were included in the survey of 12th graders for the first time in 2010. They yielded an annual prevalence rate of 17 percent for hookah smoking, with 6.5 percent of 12th-grade students smoking hookah more than five times during the year. Males had only a slightly higher prevalence rate than females -- 19.0 percent vs. 15.2 percent.
Smoking small cigars is a more prevalent behavior, with 12th graders having an annual prevalence in 2010 of 23 percent, but with only 10 percent indicating use on more than five occasions during the year. There is a larger gender difference for this form of tobacco use, with an annual prevalence of 30 percent among males compared to 16 percent among females.
"We will continue to monitor these two forms of tobacco consumption to see if they represent a growing problem among youth, and we will be examining their use among young adults, as well," states Johnston.
As for the use of illicit drugs, the proportion of young people using any illicit drug has been rising over the past three years, due largely to increased use of marijuana -- the most widely used of all the illicit drugs. The proportion of 8th graders who reported using at least one illicit drug in the prior 12 months (called annual prevalence) rose from 13 percent in 2007 to 16 percent in 2010, including a statistically significant increase of 1.6 percentage points this year. Among both 10th and 12th graders annual prevalence has increased by two percentage points since 2007. In 2010, the proportions using any illicit drug during the past year were 16 percent, 30 percent, and 38 percent in grades 8, 10, and 12 respectively.
Lifetime use was higher, of course, at 21 percent, 37 percent, and 48 percent in the three grades respectively. In other words, about half of the high school seniors in the class of 2010 have tried an illicit drug, and well over a third have used on one or more occasions in the prior 12 months.
The proportion of students reporting using any illicit drug other than marijuana has been gradually declining for some years, but that decline halted in 2010 in all three grades. The annual prevalence rates for using any illicit drug other than marijuana in the prior 12 months are 7 percnet, 12 percent, and 17 percent in grades 8, 10, and 12; the corresponding lifetime prevalence rates are 11 percent, 17 percent and 25 percent.
Marijuana use rose for all prevalence periods this year (lifetime, past year, past 30-days, and daily in the past 30-days) in all three grades under study. For the three grades combined, all of these one-year increases are statistically significant. Further, virtually all demographic subgroups are showing an increase in use.
"Though this upward shift is not yet very large, its duration and pervasiveness leave no doubt in our minds that it is real," said Lloyd Johnston, the principal investigator of the study. "Perhaps the most troublesome part of it is that daily use of marijuana increased significantly in all three grades in 2010."
Daily or near-daily use is defined as use on 20 or more occasions in the prior 30 days; the rates for grades 8, 10, and 12 were 1, 3 and 6 percent in 2010. In other words, about one in sixteen 12th graders today uses marijuana on a daily or near-daily basis.
One possible explanation for the resurgence in marijuana use is that in recent years fewer teens report seeing much danger associated with its use, even with regular use. Possibly as a result, fewer teens have shown disapproval of marijuana use over the past two or three years. Both perceived risk and disapproval continued to decline in all three grades this year.
Ecstasy provided one of the most recent surges in use of an illicit drug. Use among teens rose sharply in the late 1990s, peaked in 2001, and then fell just as sharply over the next four years or so as perceived risk rose considerably. After 2004 or 2005, perceived risk fell steadily and the investigators warned that this could lead to a rebound in use. Some of that rebound now appears to be taking place, as use rose this year in all three grades, significantly so for 8th and 10th grades.
Taking heroin using a needle did show a small but statistically significant increase in 2010, but only among 12th graders and without any concurrent changes in perceived risk, disapproval, or availability.
"Because the prevalence rates for heroin use are so low in this population, it doesn't take a lot of cases to yield a significant change," said Johnston, "so we are not yet ready to say that this is a real change. If it is real, it would be important; but we will want to see another year's data before being confident that it is."
Several classes of drugs exhibited a decline in use in 2010. The use of cocaine among 8th graders has been in decline since 1998, but did not fall any further this year. The 10th and 12th graders, however, continued their gradual, steady declines in cocaine use that began after 2007 and 2006, respectively. The 2010 annual prevalence rates for cocaine are 1.6, 2.2 and 2.9 percent in the three grades -- far lower than they were in the mid-1980s or even the mid-1990s.
Non-medical use of prescription drugs rose during the mid 1990s along with the use of nearly all illegal drugs, but while most illegal drugs peaked in the late 1990s and then began to decline, the misuse of most prescription drugs continued to climb into the 2000s. This had the effect of making them a more important part of the nation's drug use problem than they had been previously. Fortunately, misuse of most of these drugs by teens has leveled off in the past few years, as these drugs and their dangers have received much more public attention.
Amphetamines showed a pattern of peaking and then declining. The changes occurred in a staggered fashion, likely reflecting some lasting differences among class cohorts. Among 8th graders, annual prevalence peaked at 7.2 percent in 1998 and then declined to 4.2 percent by 2007.
Sedative (barbiturate) use is reported only for 12th graders. They showed a pattern of increasing use from 1992 through 2005, with annual prevalence rising from 2.8 to 7.2 percent, before beginning a steady gradual decline in the years since, with a prevalence rate of 4.8 percent in 2010. Similarly, tranquilizer use grew considerably during the 1990s and peaked in 2002 at 7.7 percent annual prevalence among 12th graders. Since then it has shown a very gradual decline, reaching 5.6 percent in 2010.
The use of a class of drugs consisting of narcotics other than heroin nearly tripled from 1992 through 2004, from an annual prevalence of 3.3 percent in 1992 among 12th graders (the only ones for whom these drugs are reported) to 9.5 percent in 2004. Use then remained level through 2009, showing a non-significant drop of 0.5 percentage points in 2010. Most of the drugs in this important class of addictive substances are analgesics (taken for pain), and two of the most important are Vicodin and OxyContin.
Where students acquire these prescription drugs is a matter of some interest. By asking those who used each drug in the past year where they got them, the investigators learned that the most common source was a friend giving the drug to the respondent, followed by a friend selling the drug to the respondent. In some cases the drugs were left over from a prescription the respondent previously had, and in some cases the drugs were taken from a relative without their permission; but these were less common sources. Only a modest proportion of the users (between 20 and 30 percent, depending on the drug) said they had bought them from a drug dealer or stranger. Almost none said that they had bought them on the Internet.
The use of a number of illicit drugs remains relatively unchanged in 2010, though most are at lower levels of use than they were 10 or 15 years ago. They include: any illicit drug other than marijuana, inhalants, LSD, hallucinogens other than LSD, PCP, crack, heroin without using a needle, OxyContin, amphetamines (including Ritalin and Adderall specifically), methamphetamine, crystal methamphetamine, several so-called "club drugs" (Rohypnol, GHB, and Ketamine), and steroids.
The investigators note that, although there has not been a rise in the use of inhalants in recent years, the proportions of teens seeing their use as dangerous declined considerably between 2001 and 2008, which may make young people more vulnerable to a resurgence of inhalant use, much as has happened with ecstasy. Fortunately, this decline in perceived risk has leveled out over the past two years.
The same is true for LSD. Perceived risk has fallen fairly dramatically among 8th graders, though it has not fallen further in 2010. This means that the newer cohorts of teenagers have less reason to avoid using LSD, should that drug make a comeback. "It leaves them more vulnerable," Johnston said. Although LSD shows a significant increase this year among 12th graders (a rise of 0.7 percentage points to 2.6 percent) the investigators are not characterizing this as an increase because it simply brings the rate back to where it was two years ago. They interpret this as reflecting sampling error.
The use of cough and cold medicines to get high has shown little systematic change since their use was first measured in 2006. These over-the-counter medications, usually containing the active ingredient dextromethorphan, are taken in doses that are multiples of the usual therapeutic dose in order to achieve the desired effect. "These drugs can be dangerous when consumed in the large quantities that young people tend to use in order to get high," state the investigators. Annual prevalence rates for the three grades in 2010 were 3.2, 5.1 and 6.6 percent in grades 8, 10, and 12, respectively.
Two drugs were added to the 12th-grade questionnaires in 2009 -- salvia and Provigil.
Salvia, or salvia divinorum, is derived from a plant grown in the mountains of Mexico. It is an herb in the mint family that can induce relatively short-acting dissociative effects when chewed, smoked, or taken as a tincture. The U.S. Drug Enforcement Administration has designated it a "drug of concern," but at present it is not controlled under the federal Controlled Substances Act. However, a number of states have restricted its sale and use, and others are considering doing so. The 2009 survey found that 5.7 percent of 12th graders indicated having used salvia during the prior 12 months, and this rate did not change significantly in 2010 at 5.5 percent. This year for the first time 8th and 10th graders were asked about their use of salvia, and 1.7 and 3.7 percent respectively said they had used salvia at least once in the past year. Clearly this drug has made some inroads in the adolescent population, but its use does not appear to be growing. As is true for many drugs, use tends to be particularly concentrated among males and those who are not college-bound.
The other drug added to the survey of 12th graders in 2009 is Provigil (modafinil), which is a prescription-controlled medicine for improving wakefulness. It is usually prescribed to people experiencing excessive sleepiness as a result of sleep disorders due to sleep apnea, shift work, or narcolepsy. The annual prevalence of using Provigil outside of medical supervision by 12th graders in 2009 was 1.8 percent and in 2010 was 1.3 percent (not a statistically significant change), suggesting that misuse of Provigil by teens is neither a serious nor a growing problem.
In general there has been a long-term decline in teen use of alcohol going back to the 1980s. The early- to mid-1990s saw a pause in this decline as alcohol use rose for several years along with the use of many of the illicit drugs. However, a sustained further decline resumed in the late 1990s -- again, along with the use of a number is illegal drugs. It continued into 2010, when 30-day prevalence for the three grades combined fell significantly by 1.6 percentage points from 28.4 percent in 2009 to 26.8 percent in 2010. The three individual grades showed some decline in 2010 (-1.2, -1.5, and -2.3 percentage points in the three grades, respectively), but only the one-year decline in 12th grade reached statistical significance.
For 12th graders 2010 marks the lowest level of alcohol use since the study's inception in 1975. For 8th and 10th graders it marks the lowest point since these grades were first included in the study in 1991. Since 1991, 30-day prevalence rates have fallen by about half among 8th graders, by close to one third among 10th graders, and by nearly one quarter among 12th graders.
The proportion of students reporting having five or more drinks in a row at least once in the two weeks prior to the survey also fell in all three grades in 2010 (by 0.6, 1.1, and 2.1 percentage points, respectively, for grades 8, 10 and 12). Again, only the 12th-grade decline reached significance; but the decline for the three grades combined (-1.2 percentage points) was significant. This year's decline in occasional heavy drinking continues the gradual decrease since about 1999; the declines in the rates since recent peak levels are on the order of one half, one third, and one quarter for the three grades.
Teenage use of anabolic steroids increased in the late 1990s, reaching peak levels in 2000 among 8th graders, 2002 among 10th graders, and 2004 among 12th graders. "The steroid problem among teens has diminished considerably over the past 10 years or so," Johnston said. Since the recent peaks, annual prevalence of steroid use has declined by over two thirds among 8th graders, by more than half in 10th graders, and by four tenths among 12th graders. There has been little change over the past two years, except for a statistically significant decline of just 0.2 percentage points among 8th graders this year. In 2010, the proportions reporting any use of anabolic steroids in the past year were only 0.5, 1.0 and 1.5 percent in grades 8, 10, and 12, respectively. Among boys, who generally have had considerably higher use than girls, the rates in 2010 were 0.7, 1.3 and 2.5 percent.
Monitoring the Future has been funded under a series of competing, investigator-initiated research grants from the National Institute on Drug Abuse, one of the National Institutes of Health. The lead investigators, in addition to Johnston, are Patrick O'Malley, Jerald Bachman, and John Schulenberg -- all research professors at the University of Michigan's Institute for Social Research. Surveys of nationally representative samples of American high school seniors were begun in 1975, making the class of 2010 the 36th such class surveyed. Surveys of 8th and 10th graders were added to the design in 1991, making the 2010 nationally representative samples the 20th such classes surveyed. The sample sizes in 2010 are 15,769 eighth graders in 147 schools, 15,586 tenth graders in 123 schools, and 15,127 twelfth graders in 126 schools, for a total of 46,482 students in 396 secondary schools. The samples are drawn separately at each grade level to be representative of students in that grade in public and private secondary schools across the coterminous United States. Schools are selected with probability proportionate to their estimated class size.
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