"The estimate of current heroin use in 2015 among people aged 12 or older was higher than the estimates in most years between 2002 and 2009, but it was similar to the estimates between 2010 and 2014 (Figure 8). However, even when there was a statistically significant difference between the 2015 estimate and prior years, the percentages were approximately the same, except for the estimate in 2014 (0.2 percent). For example, all of these estimates for current heroin use rounded to 0.1 percent. In 2014, the estimate of current heroin use was higher than in all previous years; however, the 2015 estimate does not provide strong support that the increase in 2014 signaled the start of a change in the trend. Future survey years will be useful for monitoring this trend.
"The estimate of past year heroin use in 2015 (0.3 percent) was also higher than the estimates for most years between 2002 and 2008, but it was similar to the estimates between 2009 and 2014 (Figure 9). This shift in heroin use among people aged 12 or older reflects changes in heroin use by adults aged 26 or older and, to a lesser extent, smaller increases in heroin use among young adults aged 18 to 25."

"As noted in the illicit drug use section, an estimated 22.2 million Americans aged 12 or older in 2015 were current users of marijuana (Figure 1). This number of past month marijuana users corresponds to 8.3 percent of the population aged 12 or older (Figure 3). The percentage of people aged 12 or older who were current marijuana users in 2015 was similar to the percentage in 2014, but it was higher than the percentages from 2002 to 2013. This increase in marijuana use among people aged 12 or older reflects the increase in marijuana use by adults aged 26 or older and, to a lesser extent, increases in marijuana use among young adults aged 18 to 25."

"Cannabis use has increased globally, particularly in Asia since 2009. Although epidemiological data is not available, experts from the region report a perceived increase in use. The regions with a prevalence of cannabis use that is higher than the global average continue to be West and Central Africa (12.4 per cent), Oceania (essentially Australia and New Zealand, 10.9 per cent), North America (10.7 per cent) and Western and Central Europe (7.6 per cent). Cannabis use in North America and in most parts of Western and Central Europe is considered to be stable or declining."

"In this report, estimates of the use of cocaine include use of crack cocaine. Estimates also are presented separately for crack use. In 2015, the estimate of about 1.9 million people aged 12 or older who were current users of cocaine (Figure 1) included about 394,000 current users of crack. These numbers correspond to about 0.7 percent of the population aged 12 or older who were current users of cocaine (Figure 7) and 0.1 percent who were current users of crack (Table A.1B in Appendix A). The 2015 estimate for current cocaine use was similar to the estimates in most years between 2007 and 2013, but it was higher than the estimate in 2014. The 2015 estimate of crack use was similar to the estimates in most years from 2008 to 2014. The 2015 estimates of both cocaine and crack use were lower than most of the estimates between 2002 and 2006."

"• In 2018 the proportion of 12th graders who favor legalization of marijuana was 48%, about the same as the record of 49% set in the previous year. Support for legalization has been steadily and rapidly increasing since 2008, when it was near 30%. Prior to 2008, support followed a U-shape curve, in which support levels near 30% were present at the beginning of the survey, in 1975, then dipped by half to a nadir of 15% in 1986-88, only to redouble and return to around 30% by 1995, where it hovered for a decade before rising considerably.

"• The proportion of 12th grade students who favor treating marijuana use as a crime is at the lowest level ever recorded by the survey (11%), and its trend is a mirror image of the pattern seen for support of marijuana legalization. Back around 1990 as many as 50% thought its use should be a crime.

"• Given that the percentage of 12th grade students who support legalization has never exceeded 50% in the 44 years of this study, some of the greater tolerance for marijuana use among adults²¹ apparently develops after the high school years.

"• The recent trend toward greater tolerance of marijuana use is also seen in the proportion of 12th grade students who support the sale of marijuana to adults, conditional on its use being legalized. In 2018 this proportion was 55%, the same level as in 2017 and the highest level ever recorded by the study (Table 8-8). In past years, support had reached a nadir of 38% in 1989, and then gradually increased to present levels, with a decade-long plateau between 1995 and 2005.

"• It is likely that the growing number of states that have legalized recreational marijuana use for adults plays a role in the increasing tolerance of marijuana use among 12th grade students, who may interpret increasing legalization as a sign that marijuana use is safe and state-sanctioned.

"• In 2018, 9% of 12th graders predicted they would use marijuana if it were legally available (Table 8-8). This is the second highest level recorded for this measure, with the record of 10% set last year. The percentage who predicted they would try marijuana if it were legal reached a historic high in 2018, at 16%. The percentage who reported they would not use marijuana even if it were legal significantly declined to 45%, a record low. Previous to 2018 these outcomes had been fairly similar for all graduating classes. The slight shifts that did occur were attributable mostly to the changing proportions of 12th graders who had actually used marijuana."

"The use of opioids (heroin, opium and prescription opioids) has increased in Asia since 2009, particularly in East, South-East, Central and South-West Asia. While reliable data do not exist for most parts of Africa, experts report an increase in the use of opioids there. North America 3.9 per cent), Oceania (3.0 per cent), the Near and Middle
East/South-West Asia (1.9 per cent) and East and South-Eastern Europe (1.2 per cent) show a prevalence of opioid use that is higher than the global average. The use of opiates (heroin and opium) has remained stable in some regions, nevertheless, a high prevalence is reported in the Near and Middle East/South-West Asia (1.2 per cent), primarily in Afghanistan, Iran (Islamic Republic of ) and Pakistan, as well as Central Asia (0.8 per cent), Eastern and South-Eastern Europe (0.8 per cent), North America (0.5 per cent) and West and Central Africa (0.4 per cent)."

"• Table 8-8 lists the proportions of 12th graders in 2018 who favor various legal consequences for marijuana use. The proportion who believe it should be entirely legal was 48%, near the record high set the previous year of 49%. As the percentage favoring legality increased, the percentage believing marijuana use should be a crime decreased and in 2018 was 11%, the lowest level recorded by the survey, having fallen from a peak of 53% in 1990.

"• Asked whether they thought it should be legal to sell marijuana if it were legal to use it, about two in three (66%) said “yes,” very near the historic high of 67% set the previous year. However, about 83% of those answering “yes” (55% of all respondents) would permit sale only to adults. A small minority (11%) favored the sale to anyone, regardless of age, while 19% said that sale should not be legal even if use were made legal, and 15% said they “don’t know.” Thus, while the majority subscribe to the idea of legal sale, if use is allowed, the great majority agree with the notion that sale to underage people should not be legal.

"• Most 12th graders felt that they would be little affected personally by the legalization of either the sale or the use of marijuana. Nearly half (45%) of the respondents said that they would not use the drug even if it were legal to buy and use, while others indicated that they would use it about as often as they do now (16%) or less often (1%). Only 9% said they would use it more often than they do at present, while 16% thought they would try it. Another 13% said they did not know how their behavior would be affected if marijuana were legalized. Still, this amounts to 25% of all 12th graders, or about one in four, who thought that they would try marijuana, or that their use would increase, if marijuana were legalized.

"• A study of the effects of decriminalization by several states during the late 1970s, based on MTF data, found no evidence of any impact on the use of marijuana among young people, nor on attitudes and beliefs concerning its use.¹⁸ However, it should be noted that decriminalization falls well short of the full legalization posited in the questions here. Moreover, the situation today is very different from the one in the late 1970s, with more peer disapproval and more rigorous enforcement of drug laws, at least until recently. Some more recent studies suggest that there might be an impact of decriminalization, because “youths living in decriminalized states are significantly more likely to report currently using marijuana.”¹⁹ One study using MTF data shows that prevalence of marijuana use among 12th grade Californian students significantly increased in the two years after decriminalization went into effect in 2011, and youth attitudes also became significantly more permissive.²⁰ As more states approve full legalization of recreational use for adults (as has occurred in California, Massachusetts, Michigan, Nevada, Maine, Colorado, Washington, Oregon, Alaska, Vermont, and Washington, DC), it seems quite possible that attitudes about, and use of, marijuana will change. Declines in perceived risk and disapproval of marijuana would seem the most likely attitudinal changes, and such changes may well lead to increased use among youth."

Amphetamine-Type Stimulants

"In 2014, the estimated 1.6 million people aged 12 or older who were current nonmedical users of stimulants included 569,000 people who were current methamphetamine users (Figure 8). Thus, almost two thirds of current nonmedical users of stimulants in 2014 who were aged 12 or older reported current nonmedical use of prescription stimulants but not methamphetamine.
"These numbers of nonmedical users of stimulants and methamphetamine users represent 0.6 percent of the population aged 12 or older who were current nonmedical users of stimulants (Figure 9) and 0.2 percent who were current users of methamphetamine in 2014 (Figure 10). The percentage of the population aged 12 or older in 2014 who were current nonmedical users of stimulants was higher than the percentages for most years between 2005 and 2012. Meanwhile, the percentage of the population aged 12 or older in 2014 who were current users of methamphetamine was similar to the percentages for most years between 2002 and 2013."

"• The prevalence of past month illicit drug use among adult full-time workers was 8.2 percent (Figure 2.3 and Tables 2.2 and 2.3).
"• Nearly one out of five (19.0 percent) workers aged 18 to 25 used illicit drugs during the past month. This was a higher percentage than among the 26-to-34 (10.3 percent), 35-to-49 (7.0 percent), and 50-to-64 (2.6 percent) age groups (Figure 2.3 and Table 2.2).
"• Males were more likely than females to report past month illicit drug use (9.7 vs. 6.2 percent). Males accounted for about two thirds (6.4 million) of the workers who reported past month illicit drug use (Figure 2.4 and Table 2.2).
"• The prevalence of past month illicit drug use for white adults was 8.8 percent, higher than the prevalence for Asian (2.2 percent) or Hispanic (6.7 percent) adults, and lower than that reported for adults who reported two or more races (13.5 percent). The prevalence of past month illicit drug use by Asians was lower than that reported by all other racial/ethnic groups reported here (Figure 2.5 and Table 2.2)."