The following sections offer a brief look at the extent of drug use and abuse among the U.S. population.
Marijuana remains the most commonly used illegal drug: Approximately 80 percent of current illicit drug users are marijuana or hashish users. Males ages 18 to 25 reported the highest rates of past-year and current use compared with all other age and gender groups. More than one in six males in the 18- to 25-year-old age group are current marijuana users. In 1997 approximately 11 million Americans used marijuana during the past month. Race and ethnicity were associated with marijuana use, but the relationships varied by age. Overall and among persons 18 to 34 years old, whites reported higher levels of lifetime use than blacks and Hispanics. Past-year and current rates for Hispanic adults were significantly lower than for whites and blacks. But among adults age 26 and older, blacks reported a higher level of past-month use than whites.
After 6 years of steady increases, in 1997 marijuana use remained level among eighth graders. Among 10th graders the rate of increase has decelerated, although the proportion of 10th graders reporting any marijuana use in the prior 12 months still showed some increase. There is some evidence of deceleration among 12th graders, with observed increases in 1996 and 1997 considerably lower than those observed in 1993, 1994, and 1995.
The most promising data showed that for the first time in 6 years, eighth graders reported an increase in disapproval of marijuana. There was no change in the reported availability of marijuana at any grade level.
However, marijuana-related emergency room usage continues to increase in many U.S. cities. In addition, primary marijuana use as a percentage of treatment admissions increased slightly to moderately among the Nation's cities. According to the CEWG, in many U.S. cities marijuana now exceeds cocaine as the drug most frequently detected by urinalysis among adult males arrested for any reason.  The percentage of positive urinalysis for marijuana is much higher for juveniles than it is for adults.
In 1997 an estimated 1.5 million Americans, or 0.7 percent of the population age 12 and older, were current cocaine users, a significant decline from the 5.7 million cocaine users reported in 1985. An estimated 682,000 Americans (0.3 percent of the population) were frequent cocaine users, defined as those who use cocaine on 51 or more days during the past year. Since this measure of frequent cocaine use was first estimated in 1985, no significant increases or decreases have been detected. The estimated number of current crack users was about 604,000 in 1997, and there have been no statistically significant changes since 1988.
These estimates of the extent of cocaine use based on the NHSDA may be conservative because many of the most frequent users belong to population subgroups not well represented in household surveys. Based on additional data sources that take account of users underrepresented in the NHSDA, the Office on National Drug Control Policy (ONDCP) estimates the number of chronic cocaine users at 3.6 million. 
The use of cocaine powder rose steadily in 8th, 10th, and 12th graders throughout the first half of the 1990s, but rates of cocaine use in these groups remained level in 1996 and 1997. Among eighth graders, perceived risk remained constant this year, and disapproval of use actually increased, both after an earlier period of erosion in these attitudes. The use of crack cocaine was level for all grades.
Many indicators also show that cocaine use is leveling off among the general population. Cocaine-related deaths were stable in the majority of U.S. cities reporting, and the percentage of treatment admissions for primary cocaine problems declined slightly or remained stable in most urban areas. However, supplies of cocaine remain abundant.
As in the past, the rate of current cocaine use in 1997 was highest among those ages 18 to 25 years (1.2 percent). Rates were 1.0 percent for youth ages 12 to 17 years, 0.9 percent for adults 26 to 34 years, and 0.5 percent for adults age 35 and older. The rate for young adults ages 18 to 34 was significantly lower in 1997 than in 1996. Rates of past-month cocaine use were 1.4 percent for blacks, 0.8 percent for Hispanic whites, and 0.6 percent for non-Hispanic whites. Cocaine use among men was almost twice that among women.
Estimates of lifetime heroin prevalence have ranged from 2.3 million in 1979 to 1.5 million in 1990, 2.4 million in 1996, and 2.0 million in 1997. The estimated number of current heroin users was 68,000 in 1993, 117,000 in 1994, 196,000 in 1995, 216,000 in 1996, and 325,000 in 1997, representing a statistically significant increase from 1993 to 1997.
Estimates of heroin use from the NHSDA, like estimates of cocaine use, are considered conservative due to underrepresentation of the population of users and failure to access many of the heaviest users in the sampling frame. ONDCP estimates that adjusting for this underrepresentation by use of additional data indicates that there were approximately 810,000 chronic heroin users in the United States in 1995. 
Among lifetime heroin users, the proportion that had ever smoked, sniffed, or snorted heroin increased from 55 percent in 1994 to 71 percent in 1997. At the same time, the proportion that had ever used heroin with a needle remained unchanged at approximately 55 percent in 1997. There is little difference among heroin users in terms of race or ethnicity. Males are more likely than females to report heroin use during their lifetimes.
The rates of heroin use in the student population remain quite low, but they have risen significantly among 8th, 10th, and 12th graders. It appears that snorting or smoking heroin, rather than injecting it, has played a role in heroin use. Despite this rise, more students over the past 2 years have been reporting heroin use as dangerous, a contrast to the erosion in those beliefs through the first half of the decade.
By some measures, heroin use is growing as a problem in many cities. Rates of emergency room use related to heroin have increased significantly in eight cities participating in the CEWG network. Higher quality, lower priced heroin is available throughout the Nation.
The abuse of methamphetamine-a potent psychostimulant-is an extremely serious and growing problem. Known as "speed" or "ice," methamphetamine has a high potential for abuse and dependence. Because its mood-elevating effects can vary in intensity from a few minutes to many hours, depending on the route of administration and dosage, users escalate the frequency and the size of doses to maintain their "high."
Note: Quarterly emergency room (ER) episodes due to stimulant use were tracked from 1994 to 1996. A shortage of methamphetamine was reported by epidemiologists during the last half of 1995, accounting for the significant decrease in ER episodes.
Although the drug was first used primarily in selected urban areas in the western and southwestern regions of the United States, we now are seeing high levels of methamphetamine abuse in many areas of the Midwest, in both urban and rural settings and by diverse segments of the population. Methamphetamine continues to be a problem in Hawaii and in major western cities, such as Denver, Los Angeles, and San Francisco. Increased methamphetamine availability and production are being reported in diverse areas of the country, particularly rural areas, prompting concern about more widespread use.
In 1997 an estimated 5.3 million people (2.5 percent of the population) had tried methamphetamine at some time in their lives. In 1994, the estimate was 3.8 million (1.8 percent), and in 1996 it was 4.9 million (2.3 percent). Methamphetamine-related emergency room episodes decreased by 39 percent between 1994 and 1996, after a 237-percent increase between 1990 and 1994. There was a statistically significant decrease in methamphetamine-related episodes between 1995 (16,200) and 1996 (10,800). However, there was a significant increase of 71 percent between the first half of 1996 and the second half of 1996 (from 4,000 to 6,800).
Among 12th graders, past-year methamphetamine use remained constant at 2.3 percent in 1997 after increasing the previous 4 years. Perceived risk levels and availability also remained constant.
Nicotine Use (Cigarettes and Smokeless Tobacco)
The use of tobacco products may be the Nation's most critical public health problem, largely because of the addictive properties of nicotine, a major component of tobacco. Cigarette smoking is the most prevalent form of nicotine addiction in the United States, although smokeless tobacco is also an important contributor to nicotine addiction. Most adults in the United States have had some experience with nicotine, by either smoking cigarettes or using smokeless tobacco products. In 1997 approximately 71 percent of the population age 12 or older had tried at least a few puffs of a cigarette some time in their lives.
Approximately 33 percent of the population had smoked a cigarette during the past year, and 30 percent-64 million Americans-are current smokers. These rates remained constant between 1996 and 1997. However, the use of smokeless tobacco dropped among young adults ages 18 to 25. In every age group, people who had used cigarettes in the past month were more likely to have used other illicit drugs as well.
Among adults, males are more likely than females to have ever used any nicotine products or to have used them within the past year or past month. However, the rates for adolescent males and females do not differ significantly. Whites are more likely to have ever smoked than blacks or Hispanics, and whites and blacks were more likely than Hispanics to be current smokers. Cigarette smoking is more common in nonmetropolitan areas than in metropolitan areas and is more common in southern and north central States than in States in the Northeast or West.
The MTF Study found that after 6 years of steady increase, cigarette smoking among eighth graders has leveled and may even have begun to decline. There is also evidence that smoking rates among 10th graders may be leveling. Only among 12th graders is there clear evidence of a further increase in smoking, continuing an upward march that began 5 years ago. In one encouraging sign, there has been an upward shift over the past 2 years in the proportion of students in all three grades who see great risk associated with being a pack-a-day smoker. However, cigarettes remain readily available to our youth, with 76 percent of 8th graders and 90 percent of 10th graders reporting easy access.
The impact of nicotine addiction in terms of morbidity, mortality, and economic costs to society is staggering. Tobacco kills more than 430,000 U.S. citizens each year-more than alcohol, cocaine, heroin, homicide, suicide, car accidents, fire, and AIDS combined. Tobacco use is the leading preventable cause of death in the United States. Economically, smoking is responsible for approximately 7 percent of total U.S. health care costs, an estimated $50 billion yearly. However, this cost is well below the total cost to society because it does not include burn care from smoking-related fires, perinatal care for low birth-weight infants of mothers who smoke, and medical care costs associated with diseases caused by secondhand smoke. Taken together, the direct and indirect costs of smoking are estimated at more than $100 billion per year.
Inhalants are breathable chemical vapors that produce a high when inhaled. They include solvents; gases such as butane and other spray-can propellants; and nitrites such as cyclohexyl nitrite-available to the public-amyl nitrite-available only by prescription-and butyl nitrite-now an illegal substance.
According to the 1997 NHSDA, approximately 12 million Americans (5.7 percent) reported use of inhalants at least once in their lifetime, and 883,000 people (0.4 percent) were current users. The rate of current inhalant use has remained constant since 1994. The highest current use of inhalants was among 12- to 17-year-olds.
With so many substances lumped together as inhalants, research data describing frequency and trends of inhalant abuse are uneven and sometimes contradictory. However, evidence indicates that inhalant abuse is more common among all socioeconomic levels of American youth than is typically recognized by parents and the public. For instance, the 1997 Monitoring the Future Study showed that more than one in five eighth graders had used inhalants at least once in his or her lifetime. Inhalants are most commonly used by adolescents in their early teens, with usage dropping off as students grow older. Inhalants were used by equally high percentages of 10th and 12th graders according to the NIDA survey, but 8th graders had the highest rate of use. For example, although 5.4 percent of eighth graders reported using inhalants within the past 30 days, known as "current" use, only 2.5 percent of seniors reported current use of inhalants.
A major roadblock to recognizing the size of the inhalant problem is the ready availability of products that are inhaled. Inhalants are cheap and can be purchased legally in retail stores in a variety of seemingly harmless products. As a result, adolescents who sniff inhalants to get high do not face the drug procurement obstacles that confront abusers of other drugs.
The two most commonly abused hallucinogens are PCP (phencyclidine) and LSD (lysergic acid diethylamide), also known as acid. In 1997 nearly 10 percent of the population age 12 and older reported using hallucinogens at least once during their lifetime, unchanged from the previous year. Current use and past-year use also remained unchanged. On a longer term basis, current hallucinogen use increased from 1992 to 1995 but has remained stable since then. In the aggregate population and in every adult age group, whites had higher levels of lifetime hallucinogen use than blacks and Hispanics. Most hallucinogen users are young, suburban, and middle class.
Among 8th, 10th, and 12th graders, hallucinogen use remained constant in 1997 according to the MTF Study. Consistent with this finding, the degree of risk young people reported to be associated with these drugs began to level a year earlier in all grades. Similarly, the proportion of students expressing disapproval of the use of these drugs has been level since 1996, compared with the decline in disapproval seen earlier in the 1990s.
LSD remains widely available in many U.S. cities, and prices are falling. However, indicators show declines in use in most areas. Rates of LSD- and PCP-related emergency room incidents declined throughout most of the United States, and primary hallucinogen users generally continue to constitute a small percentage of total treatment admissions.
Anabolic Steroid Use
Anabolic steroids are synthetic derivatives of testosterone that promote growth of skeletal muscle and increase lean body mass. Athletes and others who use steroids to enhance performance and improve physical appearance place themselves at risk for numerous health hazards, including liver tumors, jaundice, fluid retention, severe acne, trembling, high blood pressure, and psychiatric disorders.
Between 1989 and 1997, lifetime prevalence of anabolic steroid use among 12th graders fluctuated between a 3-percent high in 1989 and a 1.9-percent low in 1996. Annual prevalence rates for this period remained relatively stable. Among the class of 1997, 2.4 percent of high school seniors had used anabolic steroids at least once in their lifetimes-up from the class of 1996 rate of 1.9-percent lifetime use. Past-year use among seniors has been stable at 1.4 percent from 1991 to 1997. In 1997, 1.8 percent of 8th graders and 2.0 percent of 10th graders had used anabolic steroids at least once in their lifetimes, and 1.0 percent of 8th graders and 1.2 percent of 10th graders had used anabolic steroids within the past year. In all age groups, students' perceptions about the harmfulness of taking steroids and the trends in their disapproval of the use of steroids have remained relatively stable in the 1990s. However, 12th graders reported a drop in availability of steroids.