Highlights

This report presents the first information from the 2006 National Survey on Drug Use and Health (NSDUH), an annual survey sponsored by the Substance Abuse and Mental Health Services Administration (SAMHSA). The survey is the primary source of information on the use of illicit drugs, alcohol, and tobacco in the civilian, noninstitutionalized population of the United States aged 12 years old or older. The survey interviews approximately 67,500 persons each year. Unless otherwise noted, all comparisons in this report described using terms such as "increased," "decreased," or "more than" are statistically significant at the .05 level.

Illicit Drug Use

In 2006, an estimated 20.4 million Americans aged 12 or older were current (past month) illicit drug users, meaning they had used an illicit drug during the month prior to the survey interview. This estimate represents 8.3 percent of the population aged 12 years old or older. Illicit drugs include marijuana/hashish, cocaine (including crack), heroin, hallucinogens, inhalants, or prescription-type psychotherapeutics used nonmedically.
The rate of current illicit drug use among persons aged 12 or older in 2006 (8.3 percent) was similar to the rate in 2005 (8.1 percent).
Marijuana was the most commonly used illicit drug (14.8 million past month users). Among persons aged 12 or older, the rate of past month marijuana use was the same in 2006 (6.0 percent) as in 2005.
In 2006, there were 2.4 million current cocaine users aged 12 or older, which was the same as in 2005 but greater than in 2002 when the number was 2.0 million. However, the rate of current cocaine use remained stable between 2002 and 2006.
Hallucinogens were used in the past month by 1.0 million persons (0.4 percent) aged 12 or older in 2006, including 528,000 (0.2 percent) who had used Ecstasy. These estimates are similar to the corresponding estimates for 2005.
There were 7.0 million (2.8 percent) persons aged 12 or older who used prescription-type psychotherapeutic drugs nonmedically in the past month. Of these, 5.2 million used pain relievers, an increase from 4.7 million in 2005.
In 2006, there were an estimated 731,000 current users of methamphetamine aged 12 or older (0.3 percent of the population). These estimates do not differ significantly from estimates for 2002, 2003, 2004, and 2005 and are all based on new survey items added to NSDUH in 2006 to improve the reporting of methamphetamine use. These improved estimates should not be compared with estimates of methamphetamine use shown in prior NSDUH reports.
Among youths aged 12 to 17, current illicit drug use rates remained stable from 2005 to 2006. However, youth rates declined significantly between 2002 and 2006 for illicit drugs in general (from 11.6 to 9.8 percent) and for several specific drugs, including marijuana, hallucinogens, LSD, Ecstasy, prescription-type drugs used nonmedically, pain relievers, tranquilizers, and the use of illicit drugs other than marijuana.
The rate of current marijuana use among youths aged 12 to 17 declined from 8.2 percent in 2002 to 6.7 percent in 2006. Among male youths, the rate declined from 9.1 to 6.8 percent, but among female youths the rates in 2002 (7.2 percent) and 2006 (6.4 percent) were not significantly different.
There were no significant changes in past month use of any drugs among young adults aged 18 to 25 between 2005 and 2006. The rate of past year use increased for Ecstasy (from 3.1 to 3.8 percent) and decreased for inhalants (2.1 to 1.8 percent).
From 2002 to 2006, the rate of current use of marijuana among young adults aged 18 to 25 declined from 17.3 to 16.3 percent. Past month nonmedical use of prescription-type drugs among young adults increased from 5.4 percent in 2002 to 6.4 percent in 2006. This was primarily due to an increase in the rate of pain reliever use, which was 4.1 percent in 2002 and 4.9 percent in 2006. However, nonmedical use of tranquilizers also increased over the 5-year period (from 1.6 to 2.0 percent).
Among persons aged 12 or older who used pain relievers nonmedically in the past 12 months, 55.7 percent reported that the source of the drug the most recent time they used was from a friend or relative for free. Another 19.1 percent reported they got the drug from just one doctor. Only 3.9 percent got the pain relievers from a drug dealer or other stranger, and only 0.1 percent reported buying the drug on the Internet. Among those who reported getting the pain reliever from a friend or relative for free, 80.7 percent reported in a follow-up question that the friend or relative had obtained the drugs from just one doctor.
Among unemployed adults aged 18 or older in 2006, 18.5 percent were current illicit drug users, which was higher than the 8.8 percent of those employed full time and 9.4 percent of those employed part time. However, most drug users were employed. Of the 17.9 million current illicit drug users aged 18 or older in 2006, 13.4 million (74.9 percent) were employed either full or part time.
In 2006, there were 10.2 million persons aged 12 or older who reported driving under the influence of illicit drugs during the past year. This corresponds to 4.2 percent of the population aged 12 or older, similar to the rate in 2005 (4.3 percent), but lower than the rate in 2002 (4.7 percent). In 2006, the rate was highest among young adults aged 18 to 25 (13.0 percent).

Alcohol Use

Slightly more than half of Americans aged 12 or older reported being current drinkers of alcohol in the 2006 survey (50.9 percent). This translates to an estimated 125 million people, which is similar to the 2005 estimate of 126 million people (51.8 percent).
More than one fifth (23.0 percent) of persons aged 12 or older participated in binge drinking (having five or more drinks on the same occasion on at least 1 day in the 30 days prior to the survey) in 2006. This translates to about 57 million people, similar to the estimate in 2005.
In 2006, heavy drinking was reported by 6.9 percent of the population aged 12 or older, or 17 million people. This rate is similar to the rate of heavy drinking in 2005 (6.6 percent). Heavy drinking is defined as binge drinking on at least 5 days in the past 30 days.
In 2006, among young adults aged 18 to 25, the rate of binge drinking was 42.2 percent, and the rate of heavy drinking was 15.6 percent. These rates are similar to the rates in 2005.
The rate of current alcohol use among youths aged 12 to 17 was 16.6 percent in 2006. Youth binge and heavy drinking rates were 10.3 and 2.4 percent, respectively. These rates are essentially the same as the 2005 rates.
Underage (persons aged 12 to 20) past month and binge drinking rates have remained essentially unchanged since 2002. In 2006, about 10.8 million persons aged 12 to 20 (28.3 percent of this age group) reported drinking alcohol in the past month. Approximately 7.2 million (19.0 percent) were binge drinkers, and 2.4 million (6.2 percent) were heavy drinkers.
Among persons aged 12 to 20, past month alcohol use rates were 18.6 percent among blacks, 19.7 percent among Asians, 25.3 percent among Hispanics, 27.5 percent among those reporting two or more races, 31.3 percent among American Indians or Alaska Natives, and 32.3 percent among whites. The 2006 rate for American Indians or Alaska Natives is higher than the 2005 rate of 21.7 percent.
Among pregnant women aged 15 to 44, binge drinking in the first trimester dropped from 10.6 percent in 2003-2004 combined data to 4.6 percent in 2005-2006 combined data.
In 2006, an estimated 12.4 percent of persons aged 12 or older drove under the influence of alcohol at least once in the past year. This percentage has decreased since 2002, when it was 14.2 percent. The 2006 estimate corresponds to 30.5 million persons.

Tobacco Use

In 2006, an estimated 72.9 million Americans aged 12 or older were current (past month) users of a tobacco product. This represents 29.6 percent of the population in that age range. In addition, 61.6 million persons (25.0 percent of the population) were current cigarette smokers; 13.7 million (5.6 percent) smoked cigars; 8.2 million (3.3 percent) used smokeless tobacco; and 2.3 million (0.9 percent) smoked tobacco in pipes.
The rates of current use of cigarettes, smokeless tobacco, cigars, and pipe tobacco were unchanged between 2005 and 2006 among persons aged 12 or older. However, between 2002 and 2006, past month cigarette use decreased from 26.0 to 25.0 percent. Rates of past month use of cigars, smokeless tobacco, and pipe tobacco were similar in 2002 and 2006.
The rate of past month cigarette use among 12 to 17 year olds declined from 13.0 percent in 2002 to 10.4 percent in 2006. However, past month smokeless tobacco use was higher in 2006 (2.4 percent) than in 2002 (2.0 percent).
Among pregnant women aged 15 to 44, combined data for 2005 and 2006 indicated that the rate of past month cigarette use was 16.5 percent. The rate was higher among women in that age group who were not pregnant (29.5 percent).

Initiation of Substance Use (Incidence, or First-Time Use)

The illicit drug use categories with the largest number of recent initiates among persons aged 12 or older were nonmedical use of pain relievers (2.2 million) and marijuana use (2.1 million). These estimates are not significantly different from the numbers in 2005.
In 2006, there were 783,000 persons aged 12 or older who had used inhalants for the first time within the past 12 months; 77.2 percent were under age 18 when they first used. There was no significant change in the number of inhalant initiates from 2005 to 2006.
The number of recent new users of methamphetamine taken nonmedically among persons aged 12 or older was 259,000 in 2006. This estimate was not significantly different from the estimates from 2002 to 2005.
Ecstasy initiation, which had declined from 1.2 million in 2002 to about 600,000 per year during 2004 and 2005, increased to 860,000 in 2006.
Most (89.2 percent) of the 4.4 million recent alcohol initiates were younger than 21 at the time of initiation.
The number of persons aged 12 or older who smoked cigarettes for the first time within the past 12 months was 2.4 million in 2006, which was significantly greater than the estimate for 2002 (1.9 million). Most new smokers in 2006 were under age 18 when they first smoked cigarettes (61.2 percent).

Youth Prevention-Related Measures

Perceived risk is measured by NSDUH as the percentage reporting that there is great risk in the substance use behavior. Among youths aged 12 to 17, there were no changes in the perceived risk of marijuana, cocaine, or heroin between 2005 and 2006. However, between 2002 and 2006, there were increases in the perceived risk of smoking marijuana once a month (from 32.4 to 34.7 percent) and smoking marijuana once or twice a week (from 51.5 to 54.2 percent). On the other hand, the percentage of youths who perceived that trying heroin once or twice is a great risk declined from 58.5 percent in 2002 to 57.2 percent in 2006, and those who perceived that using cocaine once a month is a great risk declined from 50.5 to 49.0 percent. There was also a decrease in the perceived risk of using LSD once or twice a week, from 76.1 percent in 2005 to 74.7 percent in 2006.
The proportion of youths aged 12 to 17 who reported perceiving great risk from smoking one or more packs of cigarettes per day increased from 63.1 percent in 2002 to 68.7 percent in 2006.
About half (50.1 percent) of youths aged 12 to 17 reported in 2006 that it would be "fairly easy" or "very easy" for them to obtain marijuana if they wanted some. Around one quarter reported it would be easy to get cocaine (25.9 percent). About one in seven (14.4 percent) indicated that heroin would be "fairly" or "very" easily available, and 14.0 percent reported easy availability for LSD.
Among youths, the perceived availability decreased between 2002 and 2006 for marijuana (from 55.0 to 50.1 percent), heroin (from 15.8 to 14.4 percent), and LSD (from 19.4 to 14.0 percent). However, the percentage reporting that it would be easy to obtain cocaine showed no decline over this period (25.0 percent in 2002 and 25.9 percent in 2006).
A majority of youths (90.4 percent) in 2006 reported that their parents would strongly disapprove of their trying marijuana or hashish once or twice. Current marijuana use was much less prevalent among youths who perceived strong parental disapproval for trying marijuana or hashish once or twice than for those who did not (4.6 vs. 26.5 percent).
In 2006, 11.4 percent of youths reported that they had participated in substance use prevention programs outside of school within the past year. Approximately four fifths (79.4 percent) reported having seen or heard drug or alcohol prevention messages from sources outside of school, lower than in 2005 when the percentage was 81.1 percent. Most (59.8 percent) youths reported in 2006 that they had talked with a parent in the past year about the dangers of drug, tobacco, or alcohol use.

Substance Dependence, Abuse, and Treatment

In 2006, an estimated 22.6 million persons (9.2 percent of the population aged 12 or older) were classified with substance dependence or abuse in the past year based on criteria specified in the Diagnostic and Statistical Manual of Mental Disorders, 4^th edition (DSM-IV). Of these, 3.2 million were classified with dependence on or abuse of both alcohol and illicit drugs, 3.8 million were dependent on or abused illicit drugs but not alcohol, and 15.6 million were dependent on or abused alcohol but not illicit drugs.
Between 2002 and 2006, there was no change in the number of persons with substance dependence or abuse (22.0 million in 2002, 22.6 million in 2006).
The specific illicit drugs that had the highest levels of past year dependence or abuse in 2006 were marijuana (4.2 million), followed by cocaine (1.7 million) and pain relievers (1.6 million).
Adults aged 21 or older who had first used alcohol before age 21 were more likely than adults who had their first drink at age 21 or older to be classified with alcohol dependence or abuse (9.6 vs. 2.4 percent).
There were 4.0 million persons aged 12 or older (1.6 percent of the population) who received some kind of treatment for a problem related to the use of alcohol or illicit drugs in 2006. More than half (2.2 million) received treatment at a self-help group. There were 1.6 million persons who received treatment at a rehabilitation facility as an outpatient, 1.1 million at a mental health center as an outpatient, 934,000 at a rehabilitation facility as an inpatient, 816,000 at a hospital as an inpatient, 610,000 at a private doctor's office, 420,000 at a prison or jail, and 397,000 at an emergency room. None of these estimates changed significantly between 2005 and 2006.
More than half (2.5 million) of the 4.0 million persons who received treatment for a substance use problem in the past year received treatment for alcohol use during their most recent treatment. There were 1.2 million persons who received treatment for marijuana use during their most recent treatment. Estimates for other drugs were 928,000 persons for cocaine, 547,000 for pain relievers, 535,000 for stimulants, 466,000 for heroin, and 442,000 for hallucinogens. (Note that respondents could indicate that they received treatment for more than one substance during their most recent treatment.)
In 2006, the number of persons aged 12 or older needing treatment for an illicit drug or alcohol use problem was 23.6 million (9.6 percent of the population aged 12 or older). Of these, 2.5 million (1.0 percent of persons aged 12 or older and 10.8 percent of those who needed treatment) received treatment at a specialty facility. Thus, there were 21.1 million persons (8.6 percent of the population aged 12 or older) who needed treatment for an illicit drug or alcohol use problem but did not receive treatment at a specialty substance abuse facility in the past year.
Of the 21.1 million people in 2006 who were classified as needing substance use treatment but did not receive treatment at a specialty facility in the past year, 940,000 persons (4.5 percent) reported that they felt they needed treatment for their illicit drug or alcohol use problem. Of these 940,000 persons who felt they needed treatment, 314,000 (33.5 percent) reported that they made an effort to get treatment, and 625,000 (66.5 percent) reported making no effort to get treatment.
The number of people who felt they needed treatment and made an effort to get it among those who needed but did not receive treatment was not statistically different in 2006 (314,000) from the number reported in 2005 (296,000).

Prevalence and Treatment of Mental Health Problems

Serious psychological distress (SPD) is an overall indicator of past year nonspecific psychological distress that is constructed from the K6 scale administered to adults aged 18 or older in NSDUH.
In 2006, there were an estimated 24.9 million adults aged 18 or older in the United States with SPD in the past year. This represents 11.3 percent of all adults in this country, a rate equal to the rate in 2005.
Rates of SPD in 2006 were highest for adults aged 18 to 25 (17.7 percent) and lowest for adults aged 50 or older (6.9 percent).
The prevalence of SPD among women aged 18 or older (13.7 percent) was higher than that among men in that age group (8.7 percent).
SPD in the past year was associated with past year substance dependence or abuse in 2006. Among adults with SPD in 2006, 22.3 percent (5.6 million) were dependent on or abused illicit drugs or alcohol. The rate among adults without SPD was 7.7 percent (15.0 million).
Among the 24.9 million adults with SPD in 2006, 10.9 million (44.0 percent) received treatment for a mental health problem in the past year. Among adults with SPD, 39.0 percent received a prescription medication, 27.2 percent received outpatient treatment, and 3.9 percent received inpatient treatment for a mental health problem in the past year.
Among the 5.6 million adults with both SPD and substance dependence or abuse (i.e., a substance use disorder) in 2006, about half (50.8 percent) received mental health treatment or substance use treatment at a specialty facility; 8.4 percent received both treatment for mental health problems and specialty substance use treatment, 39.6 percent received only treatment for mental health problems, and 2.8 percent received only specialty substance use treatment.
In 2006, there were 30.4 million adults (13.9 percent of persons aged 18 or older) who had at least one major depressive episode (MDE) in their lifetime, and 15.8 million adults (7.2 percent of persons aged 18 or older) had at least one MDE in the past year.
Having MDE in the past year was associated with past year substance dependence or abuse. Among adults who had MDE in 2006, 24.3 percent were dependent on or abused alcohol or illicit drugs, while among adults without MDE only 8.1 percent were dependent on or abused alcohol or illicit drugs. Persons with MDE were more likely than those without MDE to be dependent on or abuse illicit drugs (9.4 vs. 2.1 percent) and alcohol (19.3 vs. 7.0 percent).
Among adults aged 18 or older who had MDE in the past year, 69.1 percent received treatment (i.e., saw or talked to a medical doctor or other professional or used prescription medication) for depression in the same time period.
Among adults aged 18 or older with MDE in the past year in 2006, women were more likely than men to receive treatment for depression in the past year (73.7 vs. 60.8 percent).
In 2006, there were 3.2 million youths aged 12 to 17 years (12.8 percent of the population aged 12 to 17) who had at least one MDE in their lifetime and 2.0 million youths (7.9 percent) who had MDE during the past year. These rates are lower than the 2005 estimates of 13.7 percent lifetime and 8.8 percent past year MDE.
The rate of MDE in the past year was higher for adolescent females (11.8 percent) than for adolescent males (4.2 percent).
In 2006, one third (34.6 percent) of youths with MDE in the past year had used illicit drugs in the past year, while the rate of illicit drug use among youths who did not report MDE was 18.2 percent. Similarly, the rates of past month daily cigarette use and heavy alcohol use were higher for youths with MDE (5.2 and 4.5 percent, respectively) than for youths who did not report MDE (2.5 and 2.2 percent, respectively).
In 2006, 38.9 percent of youths aged 12 to 17 with past year MDE received treatment for depression (saw or talked to a medical doctor or other professional or used prescription medication). Among youths with depression, 23.9 percent saw or talked to a medical doctor or other professional only, 2.1 percent used prescription medication only, and 12.7 percent received treatment from both sources for depression in the past year.
In 2006, there were 5.4 million youths (21.3 percent) who received treatment or counseling for emotional or behavioral problems in the year prior to the interview. Adolescent females were more likely than adolescent males to report past year treatment for mental health problems (23.0 vs. 19.6 percent, respectively).

1. Introduction

This report presents the first information from the 2006 National Survey on Drug Use and Health (NSDUH), an annual survey of the civilian, noninstitutionalized population of the United States aged 12 years old or older. Prior to 2002, the survey name was the National Household Survey on Drug Abuse (NHSDA). This initial report on the 2006 data presents national estimates of rates of use, numbers of users, and other measures related to illicit drugs, alcohol, and tobacco products. Measures related to mental health problems also are presented, including data on depression and on the co-occurrence of substance use and mental health problems. Estimates from NSDUH for States and areas within States will be presented in separate reports.

A major focus of this report is a comparison of substance use prevalence estimates between 2005 and 2006. Trends since 2002 also are discussed for some measures. Because of improvements to the survey in 2002, the 2002 data constitute a new baseline for tracking trends in substance use and other measures. Therefore, estimates from the 2002 through 2006 NSDUHs should not be compared with estimates from the 2001 and earlier surveys in the series to assess changes in substance use and mental health problems over time.

1.1. Summary of NSDUH

NSDUH is the primary source of statistical information on the use of illegal drugs by the U.S. population. Conducted by the Federal Government since 1971, the survey collects data by administering questionnaires to a representative sample of the population through face-to-face interviews at the respondent's place of residence. The survey is sponsored by the Substance Abuse and Mental Health Services Administration (SAMHSA), U.S. Department of Health and Human Services, and is planned and managed by SAMHSA's Office of Applied Studies (OAS). Data collection is conducted under contract with RTI International, Research Triangle Park, North Carolina.¹ This section briefly describes the survey methodology; a more complete description is provided in Appendix A.

NSDUH collects information from residents of households and noninstitutional group quarters (e.g., shelters, rooming houses, dormitories) and from civilians living on military bases. The survey excludes homeless persons who do not use shelters, military personnel on active duty, and residents of institutional group quarters, such as jails and hospitals. Appendix D describes surveys that cover populations outside the NSDUH target population.

Since 1999, the NSDUH interview has been carried out using computer-assisted interviewing (CAI). Most of the questions are administered with audio computer-assisted self-interviewing (ACASI). ACASI is designed to provide the respondent with a highly private and confidential means of responding to questions to increase the level of honest reporting of illicit drug use and other sensitive behaviors. Less sensitive items are administered by interviewers using computer-assisted personal interviewing (CAPI).

The 2006 NSDUH employed a State-based design with an independent, multistage area probability sample within each State and the District of Columbia. The eight States with the largest population (which together account for 48 percent of the total U.S. population aged 12 or older) were designated as large sample States (California, Florida, Illinois, Michigan, New York, Ohio, Pennsylvania, and Texas). For these States, the design provided a sample sufficient to support direct State estimates. For the remaining 42 States and the District of Columbia, smaller, but adequate, samples support State estimates using small area estimation (SAE) techniques. The design oversampled youths and young adults, so that each State's sample was approximately equally distributed among three age groups: 12 to 17 years, 18 to 25 years, and 26 years or older.

Nationally, 137,057 addresses were screened for the 2006 survey, and 67,802 completed interviews were obtained. The survey was conducted from January through December 2006. Weighted response rates for household screening and for interviewing were 90.6 and 74.2 percent, respectively. See Appendix B for more information on NSDUH response rates.

1.2. Trend Measurement

Although the design of the 2002 through 2006 NSDUHs is similar to the design of the 1999 through 2001 surveys, there are important methodological differences that affect the comparability of the 2002-2006 estimates with estimates from prior surveys. In addition to the name change, each NSDUH respondent completing the interview is now given an incentive payment of $30. These changes, implemented in 2002 and continued subsequently, resulted in an improvement in the response rate, but also affected respondents' reporting of items that are the basis of prevalence measures produced each year. Comparability also may be affected by improved data collection quality control procedures that were introduced beginning in 2001 and by the incorporation of new population data from the 2000 decennial census into NSDUH sample weighting procedures. Analyses of the effects of these factors on NSDUH estimates have shown that 2002 and later data should not be compared with 2001 and earlier data from the survey series to assess changes over time. Appendix C of the 2004 NSDUH report on national findings discusses this issue in more detail (see OAS, 2005b).

1.3. Change in Methamphetamine Use Estimates

This report includes new estimates of methamphetamine use based on data obtained from survey items added to NSDUH in 2005 and 2006. The new survey items were added to better account for how methamphetamine is supplied and obtained. Unlike other stimulants that are available by prescription, most methamphetamine in the United States is supplied through illicit manufacturing and trafficking rather than through the conventional prescription drug distribution process. Therefore, one concern is that methamphetamine use may have been underestimated in NSDUH due to its inclusion within a set of questions about prescription-type drugs. Specifically, survey respondents who used methamphetamine might not have reported its use when questions about it were asked in the context of other questions about prescription pharmaceuticals.

Section B.4.6 in Appendix B provides a discussion of the new items and the process used to generate the prevalence estimates based on them. The new estimates in this report, discussed in Chapter 2, are generally 15 to 25 percent higher than estimates of methamphetamine use published in prior reports. To assess trends in this report, a statistical adjustment was applied to 2002-2005 methamphetamine data, resulting in estimates comparable with the 2006 estimates. Because of these changes, the methamphetamine use estimates presented here are different from those shown in prior NSDUH reports and should not be compared or combined with them. In addition, because of the differences in measurement, the methamphetamine use estimates are not presented with the estimates for other drugs in the detailed tables posted to the SAMHSA website and in the tables of Appendix G in this report, but are included in a separate set of tables.

It is important to note that only the methamphetamine use estimates have been changed. Estimates for the more general drug use categories that include methamphetamine (i.e., stimulants used nonmedically, prescription psychotherapeutic drugs used nonmedically, use of illicit drugs other than marijuana, and illicit drug use) have not been modified and are comparable with those presented in previous NSDUH reports. However, estimates for these grouped categories of drugs should not be compared or combined with the new methamphetamine use estimates. Similarly, initiation estimates discussed in Chapter 5 do not incorporate the new methamphetamine items. It is expected that the 2007 NSDUH data will fully integrate the new survey items on methamphetamine with existing incidence and prevalence measures for other drugs.

1.4. Format of Report and Explanation of Tables

This report has separate chapters that discuss the national findings on seven topics: use of illicit drugs; use of alcohol; use of tobacco products; initiation of substance use; prevention-related issues; substance dependence, abuse, and treatment; and mental health problems and treatment. A final chapter summarizes the results and discusses key findings in relation to other research and survey results. Technical appendices describe the survey (Appendix A), provide technical details on the statistical methods and measurement (Appendix B), offer key NSDUH definitions (Appendix C), discuss other sources of related data (Appendix D), list the references cited in the report (as well as other relevant references) (Appendix E), and present selected tabulations of estimates (Appendices F and G).

Tables, text, and figures present prevalence measures for the population in terms of both the number of persons and the percentage of the population. Substance use tables show prevalence estimates by lifetime (i.e., ever used), past year, and past month use. Analyses focus primarily on past month use, which also is referred to as "current use." Tables and figures in which estimates are presented by year have footnotes indicating whether the 2006 estimates are significantly different from 2005 or earlier estimates.

Statistical tests have been conducted for all statements appearing in the text of the report that compare estimates between years or subgroups of the population. Unless explicitly stated that a difference is not statistically significant, all statements that describe differences are significant at the .05 level. Statistically significant differences are described using terms such as "higher," "lower," "increased," and "decreased." Statements that use terms such as "similar," "no difference," "same," or "remained steady" to describe the relationship between estimates denote that a difference is not statistically significant. In addition, a set of estimates for survey years or population subgroups may be presented without a statement of comparison, in which case a statistically significant difference between these estimates is not implied and testing was not conducted.

All estimates presented in the report have met the criteria for statistical reliability (see Section B.2.2 of Appendix B). Estimates that do not meet these criteria are suppressed and do not appear in tables, figures, or text. Also, subgroups with suppressed estimates are not included in statistical tests of comparisons. For example, a statement that "whites had the highest prevalence" means that the rate among whites was higher than the rate among all nonsuppressed racial/ethnic subgroups, but not necessarily higher than the rate among a subgroup for which the estimate was suppressed.

Data are presented for racial/ethnic groups based on current guidelines for collecting and reporting race and ethnicity data (Office of Management and Budget [OMB], 1997). Because respondents were allowed to choose more than one racial group, a "two or more races" category is presented that includes persons who reported more than one category among the basic groups listed in the survey question (white, black or African American, American Indian or Alaska Native, Native Hawaiian, Other Pacific Islander, Asian, Other). Respondents choosing both Native Hawaiian and Other Pacific Islander but no other categories mentioned above are classified in the combined "Native Hawaiian or Other Pacific Islander" category instead of the "two or more race" category. It should be noted that, except for the "Hispanic or Latino" group, the racial/ethnic groups discussed in this report include only non-Hispanics. The category "Hispanic or Latino" includes Hispanics of any race.

Data also are presented for four U.S. geographic regions and nine geographic divisions within these regions. These regions and divisions, defined by the U.S. Census Bureau, consist of the following groups of States:

Northeast Region - New England Division: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, Vermont; Middle Atlantic Division: New Jersey, New York, Pennsylvania.

Midwest Region - East North Central Division: Illinois, Indiana, Michigan, Ohio, Wisconsin; West North Central Division: Iowa, Kansas, Minnesota, Missouri, Nebraska, North Dakota, South Dakota.

South Region - South Atlantic Division: Delaware, District of Columbia, Florida, Georgia, Maryland, North Carolina, South Carolina, Virginia, West Virginia; East South Central Division: Alabama, Kentucky, Mississippi, Tennessee; West South Central Division: Arkansas, Louisiana, Oklahoma, Texas.

West Region - Mountain Division: Arizona, Colorado, Idaho, Montana, Nevada, New Mexico, Utah, Wyoming; Pacific Division: Alaska, California, Hawaii, Oregon, Washington.

Geographic comparisons also are made based on county type, a variable that reflects different levels of urbanicity and metropolitan area inclusion of counties, based on metropolitan area definitions issued by the OMB in June 2003 (OMB, 2003). For this purpose, counties are grouped based on the 2003 rural-urban continuum codes. These codes were originally developed by the U.S. Department of Agriculture (Butler & Beale, 1994). Each county is either inside or outside a metropolitan statistical area (MSA), as defined by the OMB.

Large metropolitan areas have a population of 1 million or more. Small metropolitan areas have a population of fewer than 1 million. Small metropolitan areas are further classified based on whether they have a population of 250,000 or more. Nonmetropolitan areas are areas outside MSAs. Counties in nonmetropolitan areas are further classified based on the number of people in the county who live in an urbanized area, as defined by the Census Bureau at the subcounty level. "Urbanized" counties have a population of 20,000 or more in urbanized areas, "less urbanized" counties have at least 2,500 but fewer than 20,000 population in urbanized areas, and "completely rural" counties have fewer than 2,500 population in urbanized areas.

1.5. Other NSDUH Reports and Data

Other reports focusing on specific topics of interest will be produced using the 2006 NSDUH data and made available on SAMHSA's website. A report on State-level estimates for 2005-2006 will be available in early 2008.

A comprehensive set of tables, referred to as "detailed tables," is available through the Internet at http://www.oas.samhsa.gov. The tables are organized into sections based primarily on the topic, and most tables are provided in several parts, showing population estimates (e.g., numbers of drug users), rates (e.g., percentages of population using drugs), and standard errors of all nonsuppressed estimates. A small subset of these detailed tables has been selected for inclusion in Appendices F and G of this report. The appendix tables can be mapped back to the detailed tables by using the table number in parentheses in the upper left corner of each table (e.g., Table G.1 in Appendix G is Table 8.1A in the detailed tables). Additional methodological information on NSDUH, including the questionnaire, is available electronically at the same Web address.

Brief descriptive reports and in-depth analytic reports focusing on specific issues or population groups also are produced by OAS. A complete listing of previously published reports from NSDUH and other data sources is available from OAS. Most of these reports also are available through the Internet (http://www.oas.samhsa.gov). In addition, OAS makes public use data files available to researchers through the Substance Abuse and Mental Health Data Archive (SAMHDA, 2007) at http://www.icpsr.umich.edu/SAMHDA/index.html. Currently, files are available from the 1979 to 2005 surveys. The 2006 NSDUH public use file will be available by the end of 2007.

2. Illicit Drug Use

The National Survey on Drug Use and Health (NSDUH) obtains information on nine different categories of illicit drug use: use of marijuana, cocaine, heroin, hallucinogens, and inhalants; and the nonmedical use of prescription-type pain relievers, tranquilizers, stimulants, and sedatives. In these categories, hashish is included with marijuana, and crack is considered a form of cocaine. Several drugs are grouped under the hallucinogens category, including LSD, PCP, peyote, mescaline, mushrooms, and "Ecstasy" (MDMA). Inhalants include a variety of substances, such as nitrous oxide, amyl nitrite, cleaning fluids, gasoline, spray paint, other aerosol sprays, and glue. The four categories of prescription-type drugs (pain relievers, tranquilizers, stimulants, and sedatives) cover numerous pharmaceutical drugs available by prescription and drugs within these groupings that may be manufactured illegally, such as methamphetamine, which is included under stimulants. Respondents are asked to report only "nonmedical" use of these drugs, defined as use without a prescription of the individual's own or simply for the experience or feeling the drugs caused. Use of over-the-counter drugs and legitimate use of prescription drugs are not included. NSDUH reports combine the four prescription-type drug groups into a category referred to as "psychotherapeutics."

Estimates of "illicit drug use" reported from NSDUH reflect the use of any of the nine drug categories listed above. Use of alcohol and tobacco products, while illegal for youths, is not included in these estimates, but is discussed in Chapters 3 and 4.

This chapter includes new estimates of methamphetamine use based on data obtained from survey items added to NSDUH in 2005 and 2006. The new survey items were added to better account for how methamphetamine is supplied and obtained. Unlike other stimulants that are available by prescription, most methamphetamine is supplied through illicit manufacturing and trafficking rather than through the conventional prescription drug distribution process. Therefore, one concern is that methamphetamine use may have been underestimated in NSDUH due to its inclusion within a set of questions about prescription-type drugs. Specifically, respondents who used methamphetamine might not have reported its use when questions about it were asked in the context of other questions about prescription pharmaceuticals. Section B.4.6 in Appendix B provides a discussion of the new items and the process used to generate the adjusted estimates based on them.

The new methamphetamine use estimates in this report are generally 15 to 25 percent higher than estimates of methamphetamine use published in prior reports. Estimates for stimulant use and use of psychotherapeutic drugs do not incorporate data from the new items. To assess trends, a statistical adjustment was applied to the 2002-2005 methamphetamine use data, resulting in estimates comparable with the 2006 estimates. Because of these changes, the methamphetamine use estimates presented here are different from those in prior NSDUH reports and should not be compared or combined with them. In addition, because of the differences in measurement, the methamphetamine use estimates are not presented with the estimates for other drugs in the 2006 detailed tables posted on the Substance Abuse and Mental Health Services Administration (SAMHSA) website or in Appendix G's tables in this report, but they are included in Tables B.6 and B.7 in Section B.4.6 of Appendix B, which also presents further methodological information.

It is important to note that only the methamphetamine use estimates have been changed. Estimates for the more general drug use categories that include methamphetamine use (i.e., stimulants used nonmedically, prescription psychotherapeutic drugs used nonmedically, use of illicit drugs other than marijuana, and illicit drug use) have not been modified and are comparable with those presented in previous NSDUH reports. However, estimates for use of these grouped categories of drugs should not be compared or combined with the new methamphetamine use estimates. It is expected that the 2007 NSDUH data will fully integrate the new survey items on methamphetamine use with existing incidence and prevalence measures for other drugs.

In 2006, an estimated 20.4 million Americans aged 12 or older were current (past month) illicit drug users, meaning they had used an illicit drug during the month prior to the survey interview. This estimate represents 8.3 percent of the population aged 12 years old or older.
The overall rate of current illicit drug use among persons aged 12 or older in 2006 (8.3 percent) was similar to the rate in 2005 (8.1 percent) and has remained stable since 2002 (8.3 percent).
Marijuana was the most commonly used illicit drug (14.8 million past month users) (Figure 2.1). In 2006, marijuana was used by 72.8 percent of current illicit drug users and was the only drug used by 52.8 percent of them. Illicit drugs other than marijuana were used by 9.6 million persons or 47.2 percent of illicit drug users aged 12 or older. Current use of other drugs but not marijuana was reported by 27.2 percent of illicit drug users, and 20.0 percent used both marijuana and other drugs.
Among persons aged 12 or older, the overall rate of past month marijuana use in 2006 (6.0 percent) was the same as in 2005 and was similar to the rates in earlier years going back to 2002 (Figure 2.2).

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Figure 2.1 Past Month Use of Specific Illicit Drugs among Persons Aged 12 or Older: 2006

Figure 2.1

¹Estimates for methamphetamine use incorporate data from new questions added in 2005 and 2006 that are not included in estimates for use of illicit drugs other than marijuana, use of psychotherapeutics, or stimulant use. See the introductory paragraphs of this chapter for further information.

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Figure 2.2 Past Month Use of Selected Illicit Drugs among Persons Aged 12 or Older: 2002-2006

Figure 2.2

⁺Difference between this estimate and the 2006 estimate is statistically significant at the .05 level.

An estimated 5.2 million persons were current nonmedical users of prescription pain relievers in 2006, which is more than the estimated 4.7 million in 2005. However, the change in the rate of current nonmedical use of pain relievers between 2005 and 2006 (1.9 and 2.1 percent, respectively) was not statistically significant.
In 2006, there were 2.4 million current cocaine users, the same as in 2005 (2.4 million) but more than in 2002 (2.0 million). However, the rate of current cocaine use remained stable between 2002 and 2006 (Figure 2.2). The number of past month crack users was similar in 2005 and 2006 with 682,000 and 702,000, respectively.
The number of current heroin users increased from 136,000 in 2005 to 338,000 in 2006, and the corresponding prevalence rate increased from 0.06 to 0.14 percent.
Hallucinogens were used in the past month by 1.0 million persons (0.4 percent) in 2006, including 528,000 (0.2 percent) who had used Ecstasy. These estimates are similar to the corresponding estimates for 2005. However, lifetime use of Ecstasy increased from 10.2 million persons in 2002 to 12.3 million in 2006 (4.3 to 5.0 percent of persons aged 12 or older), but past year use of Ecstasy decreased from 3.2 million (1.3 percent) to 2.1 million (0.9 percent) over the same period.
There were 9.6 million people aged 12 or older (3.9 percent) who were current users of illicit drugs other than marijuana in 2006. Most (7.0 million persons, or 2.8 percent of the population) used psychotherapeutic drugs nonmedically. In addition to the estimated 5.2 million nonmedical users of pain relievers in 2006, 1.8 million used tranquilizers, 1.2 million used stimulants, and 385,000 used sedatives. The numbers of nonmedical users of tranquilizers, stimulants, and sedatives were similar to the corresponding numbers in 2005, and the percentage rates also remained stable.
In 2006, there were an estimated 731,000 current users of methamphetamine aged 12 or older. This constitutes 0.3 percent of the population. These estimates do not differ significantly from those for 2002, 2003, 2004, and 2005. However, the rate of lifetime methamphetamine use in 2006 (5.8 percent) was higher than that in 2005 (5.2 percent) but lower than that in 2002 (6.5 percent).

Age

Rates of past month illicit drug use varied with age. Through the adolescent years from 12 to 17, the rates of current illicit drug use increased from 3.9 percent at ages 12 or 13 to 9.1 percent at ages 14 or 15 to 16.0 percent at ages 16 or 17 (Figure 2.3). The highest rate was among persons aged 18 to 20 (22.2 percent). The rate was 18.3 percent among those aged 21 to 25 and declined with increasing age among adults aged 26 or older.

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Figure 2.3 Past Month Illicit Drug Use among Persons Aged 12 or Older, by Age: 2006

Figure 2.3

Although adults aged 26 or older were less likely to be current drug users than youths aged 12 to 17 or young adults aged 18 to 25 (6.1 vs. 9.8 and 19.8 percent, respectively), there were more drug users aged 26 or older (11.4 million) than in the 12-to-17-year age group (2.5 million) and 18-to-25-year age group (6.5 million) combined.
Current illicit drug use remained stable from 2005 to 2006 among youths aged 12 to 17, young adults aged 18 to 25, and adults aged 26 or older (Figure 2.4). From 2002 to 2006, however, the rate of illicit drug use among 12 to 17 year olds decreased from 11.6 to 9.8 percent.

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Figure 2.4 Past Month Illicit Drug Use among Persons Aged 12 or Older, by Age: 2002-2006

Figure 2.4

⁺Difference between this estimate and the 2006 estimate is statistically significant at the .05 level.

Youths Aged 12 to 17

In 2006, 9.8 percent of youths aged 12 to 17 were current illicit drug users: 6.7 percent used marijuana, 3.3 percent engaged in nonmedical use of prescription-type drugs, 1.3 percent used inhalants, 0.7 percent used hallucinogens, and 0.4 percent used cocaine (Figure 2.5).

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Figure 2.5 Past Month Use of Selected Illicit Drugs among Youths Aged 12 to 17: 2002-2006

Figure 2.5

⁺Difference between this estimate and the 2006 estimate is statistically significant at the .05 level.

Among youths aged 12 to 17, the types of drugs used in the past month varied by age group. Among 12 or 13 year olds, 2.0 percent used prescription-type drugs nonmedically, 1.2 percent used inhalants, and 0.9 percent used marijuana. Among 14 or 15 year olds, marijuana was the dominant drug used (5.8 percent), followed by prescription-type drugs used nonmedically (3.1 percent), and then by inhalants (1.7 percent). Marijuana also was the most commonly used drug among 16 or 17 year olds (13.0 percent), followed by prescription-type drugs used nonmedically (4.7 percent), and then by hallucinogens (1.3 percent), inhalants (1.1 percent), and cocaine (0.8 percent).
Current illicit drug use rates remained stable from 2005 to 2006 among youths aged 12 to 17. However, rates of current use declined significantly from 2002 to 2006 for any illicit drug and several specific drugs (including marijuana, hallucinogens, LSD, Ecstasy, prescription-type drugs used nonmedically, pain relievers, tranquilizers, and the use of illicit drugs other than marijuana) (Figures 2.4 and 2.5). For any illicit drug use, the rates were 11.6 percent in 2002, 11.2 percent in 2003, 10.6 percent in 2004, 9.9 percent in 2005, and 9.8 percent in 2006.
The rate of current marijuana use among youths aged 12 to 17 declined from 8.2 percent in 2002 to 6.7 percent in 2006. Significant declines were also evident between 2002 and 2006 for past year use (from 15.8 to 13.2 percent) and lifetime use (from 20.6 to 17.3 percent).
Prevalence rates among 12 to 17 year olds also were lower in 2006 than in 2002 for current use of illicit drugs other than marijuana; nonmedical use of psychotherapeutics, pain relievers, and tranquilizers; and use of hallucinogens, LSD, and Ecstasy. The rate for illicit drugs other than marijuana declined from 5.7 percent in 2002 to 4.9 percent in 2006; nonmedical use of psychotherapeutic drugs decreased from 4.0 to 3.3 percent; nonmedical use of pain relievers declined from 3.2 to 2.7 percent; and nonmedical use of tranquilizers decreased from 0.8 to 0.5 percent. Adolescents' current use of hallucinogens declined from 1.0 percent in 2002 to 0.7 percent in 2006, reflecting decreases in current use of Ecstasy (from 0.5 to 0.3 percent) and LSD (from 0.2 to 0.1 percent).

Young Adults Aged 18 to 25

Rates of current use of illicit drugs were higher for young adults aged 18 to 25 (19.8 percent) than for youths aged 12 to 17 and adults aged 26 or older, with 16.3 percent using marijuana, 6.4 percent using prescription-type drugs nonmedically, 2.2 percent using cocaine, and 1.7 percent using hallucinogens (Figure 2.6).

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Figure 2.6 Past Month Use of Selected Illicit Drugs among Young Adults Aged 18 to 25: 2002-2006

Figure 2.6

⁺Difference between this estimate and the 2006 estimate is statistically significant at the .05 level.

There were no significant changes in past month use of any drugs among young adults aged 18 to 25 between 2005 and 2006. The rate of past year use increased for Ecstasy (from 3.1 to 3.8 percent) and decreased for inhalants (2.1 to 1.8 percent).
From 2002 to 2006, the rate of current use of marijuana among young adults aged 18 to 25 declined from 17.3 to 16.3 percent. Past month nonmedical use of prescription-type drugs among young adults increased from 5.4 percent in 2002 to 6.4 percent in 2006. This was primarily due to an increase in the rate of pain reliever use, which was 4.1 percent in 2002 and 4.9 percent in 2006. However, nonmedical use of tranquilizers also increased over the 5-year period (from 1.6 to 2.0 percent).
Among young adults aged 18 to 25, lifetime use of hallucinogens decreased from 24.2 percent in 2002 to 20.2 percent in 2006. Similarly, past year use of hallucinogens decreased between 2002 and 2006 (8.4 and 6.6 percent, respectively). Lifetime and past year nonmedical use of psychotherapeutic drugs increased between 2002 and 2006 (27.7 vs. 30.3 percent for lifetime use and 14.2 vs. 15.5 percent for past year use), with increases in the rates of pain reliever and tranquilizer use.

Adults Aged 26 or Older

Among adults aged 26 or older, 6.1 percent reported current illicit drug use in 2006 (Figure 2.4). In this age group, 4.2 percent used marijuana, and 2.2 percent used prescription-type drugs nonmedically. Less than 1 percent used cocaine (0.8 percent), hallucinogens (0.1 percent), and inhalants (0.2 percent). The only significant change between 2005 and 2006 in the rates of past month use among adults in this age group involved heroin, which increased from 0.03 to 0.14 percent. Lifetime nonmedical use of OxyContin^® among adults aged 26 or older increased from 0.9 percent in 2005 to 1.1 percent in 2006, and past year use of stimulants and heroin also increased (stimulants, from 0.6 to 0.9 percent; heroin, from 0.1 to 0.2 percent).
Among adults aged 50 to 59, the rate of current illicit drug use increased between 2002 and 2005, then remained unchanged in 2006 (Figure 2.7). For those aged 50 to 54, the rate increased from 3.4 in 2002 to 6.0 percent in 2006. Among those aged 55 to 59, current illicit drug use showed a mixed trend with no significant difference between the rates in 2002 and 2006. These patterns and trends may partially reflect the aging into these age groups of the baby boom cohort, whose lifetime rates of illicit drug use are higher than those of older cohorts.

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Figure 2.7 Past Month Illicit Drug Use among Adults Aged 50 to 59: 2002-2006

Figure 2.7

⁺Difference between this estimate and the 2006 estimate is statistically significant at the .05 level.

Gender

As in prior years, males were more likely than females among persons aged 12 or older to be current illicit drug users in 2006 (10.5 vs. 6.2 percent, respectively). The rate of past month marijuana use for males was about twice as high as the rate for females (8.1 vs. 4.1 percent) (Figure 2.8). However, males and females had similar rates of past month use of stimulants (0.5 percent for both males and females), Ecstasy (0.2 percent for both), sedatives (0.1 and 0.2 percent, respectively), OxyContin^® (0.1 percent for both), LSD (0.1 and less than 0.1 percent), and PCP (less than 0.1 percent for both).

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Figure 2.8 Past Month Use of Selected Drugs among Persons Aged 12 or Older, by Gender: 2006

Figure 2.8

From 2005 to 2006, the rate of past month nonmedical use of prescription-type psychotherapeutic drugs increased from 2.8 to 3.2 percent among males aged 12 or older, mirroring an increase in the nonmedical use of pain relievers (from 2.1 to 2.5 percent). The rate of current heroin use also increased among males (from 0.1 to 0.2 percent). There were no significant changes from 2005 to 2006 in the rate of past month drug use among females aged 12 or older.
Among youths aged 12 to 17, the rate of current illicit drug use was similar for boys (9.8 percent) and girls (9.7 percent). In 2006, male and female adolescents had similar rates of current marijuana use (6.8 and 6.4 percent) (Figure 2.9) and nonmedical use of prescription-type psychotherapeutics (3.1 and 3.5 percent, respectively).
Past month marijuana use among male youths aged 12 to 17 declined gradually from 9.1 percent in 2002 to 6.8 percent in 2006. Among female youths, the trend was less clear with the rates in 2006 (6.4 percent) and 2002 (7.2 percent) not being significantly different.

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Figure 2.9 Past Month Marijuana Use among Youths Aged 12 to 17, by Gender: 2002-2006

Figure 2.9

⁺Difference between this estimate and the 2006 estimate is statistically significant at the .05 level.

Pregnant Women

Among pregnant women aged 15 to 44 years, 4.0 percent reported using illicit drugs in the past month based on combined 2005 and 2006 NSDUH data. This rate was significantly lower than the rate among women aged 15 to 44 who were not pregnant (10.0 percent). The 2003-2004 combined rate of current illicit drug use among pregnant women (4.6 percent) was not significantly different from the 2005-2006 combined rate.

Race/Ethnicity

Current illicit drug use varied by race/ethnicity in 2006. Among persons aged 12 or older, the rate was lowest among Asians (3.6 percent). Rates were 13.7 percent for American Indians or Alaska Natives, 9.8 percent for blacks, 8.9 percent for persons reporting two or more races, 8.5 percent for whites, 7.5 percent for Native Hawaiians or Other Pacific Islanders, and 6.9 percent for Hispanics.
Among youths aged 12 to 17 in 2006, the rate of current illicit drug use among American Indians or Alaska Natives was about twice the overall rate among youths (18.7 vs. 9.8 percent, respectively). The rates were 11.8 percent among youths reporting two or more races, 10.2 percent among blacks, 10.0 percent among whites, 8.9 percent among Hispanics, and 6.7 percent among Asians.
There were no statistically significant changes between 2005 and 2006 in the rate of current illicit drug use for any racial/ethnic subgroup among persons aged 12 or older or among youths aged 12 to 17. Among young adults aged 18 to 25 who reported two or more races, the rate of current illicit drug use decreased from 31.8 percent in 2005 to 22.4 percent in 2006. In that 18-to-25-year age group, 28.5 percent of American Indians or Alaska Natives, 22.7 percent of whites, 17.3 percent of blacks, 13.9 percent of Hispanics, and 9.0 percent of Asians were current illicit drug users in 2006.

Education

Illicit drug use in 2006 varied by educational status. Among adults aged 18 or older, the rate of current illicit drug use was lower for college graduates (5.9 percent) than for those who did not graduate from high school (9.2 percent), high school graduates (8.6 percent), and those with some college (9.1 percent). However, adults who had graduated from college were more likely to have tried illicit drugs in their lifetime when compared with adults who had not completed high school (50.1 vs. 37.2 percent). Among college graduates, the rate of current illicit drug use increased from 5.0 percent in 2005 to 5.9 percent in 2006.

College Students

In the college-aged population (persons aged 18 to 22 years old), the rate of current use of illicit drugs was lower among full-time college students (19.2 percent) than among other persons aged 18 to 22 years, which includes part-time college students, students in other grades, and nonstudents (22.6 percent). Current illicit drug use among college students and other 18 to 22 year olds did not change between 2005 and 2006.
There was a significant decrease in current use of crack among persons aged 18 to 22 who were not full-time college students, from 0.6 percent in 2005 to 0.2 percent in 2006. The rate was unchanged among full-time college students (0.1 percent in both 2005 and 2006).

Employment

Current illicit drug use differed by employment status in 2006. Among adults aged 18 or older, the rate of drug use was higher for unemployed persons (18.5 percent) than for those who were employed full time (8.8 percent) or part time (9.4 percent). These rates were all similar to the corresponding rates in 2005.
Although the rate of past month illicit drug use was higher among unemployed persons compared with those from other employment groups, most drug users were employed. Of the 17.9 million current illicit drug users aged 18 or older in 2006, 13.4 million (74.9 percent) were employed either full or part time.

Geographic Area

Among persons aged 12 or older, the rate of current illicit drug use in 2006 was 9.5 percent in the West, 8.9 percent in the Northeast, 7.9 percent in the Midwest, and 7.4 percent in the South.
Past year methamphetamine use was higher in the West (1.6 percent) than in the Northeast (0.3 percent), Midwest (0.5 percent) or South (0.7 percent) in 2006 (Figure 2.10). The rates of past year use in 2006 were similar to those in 2002 in each region.
Among youths aged 12 to 17, there was evidence of regional differences in the trends of marijuana use between 2002 and 2006 (Figure 2.11). Current marijuana use rates declined in the Northeast, Midwest, and South between 2002 and 2006. In the West, the rates were steady between 2002 and 2004 (8.0 percent in 2002, 8.7 percent in 2003, and 9.3 percent in 2004) and then declined to 6.8 percent in 2005 and remained steady at 7.3 percent in 2006.

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Figure 2.10 Past Year Methamphetamine Use among Persons Aged 12 or Older, by Geographic Region: 2006

Figure 2.10

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Figure 2.11 Past Month Marijuana Use among Youths Aged 12 to 17, by Geographic Region: 2002-2006

Figure 2.11

⁺Difference between this estimate and the 2006 estimate is statistically significant at the .05 level.

The rate of current illicit drug use in metropolitan areas was higher than the rate in nonmetropolitan areas in 2006. The rates were 8.7 percent in large metropolitan counties, 8.3 percent in small metropolitan counties, and 6.8 percent in nonmetropolitan counties as a group. Within nonmetropolitan areas, counties that were urbanized had a rate of 7.1 percent, less urbanized counties had a rate of 6.5 percent, while completely rural counties had a rate of 7.8 percent. The rates in 2005 were similar to those in 2006.
The rate of current illicit drug use among the population aged 12 or older in completely rural counties in 2006 (7.8 percent) was similar to that observed in 2002 (6.7 percent) and 2005 (5.1 percent) but higher than the rate in 2003 (3.1 percent) and 2004 (4.6 percent).

Criminal Justice Populations

In 2006, there were an estimated 1.6 million adults aged 18 or older on parole or other supervised release from prison during the past year. Over one fourth of these (29.7 percent) were current illicit drug users, higher than the 7.9 percent among adults not on parole or supervised release.
Among the 4.6 million adults on probation at some time in the past year, 31.9 percent reported current illicit drug use in 2006. This was higher than the rate of 7.6 percent among adults not on probation in 2006.

Frequency of Use

In 2006, among past year marijuana users aged 12 or older, 12.3 percent used marijuana on 300 or more days within the past 12 months. This translates into 3.1 million using marijuana on a daily or almost daily basis over a 12-month period, similar to the estimate in 2005. Among past month marijuana users aged 12 or older, 34.4 percent (5.1 million) used the drug on 20 or more days in the past month.

Association with Cigarette and Alcohol Use

In 2006, the rate of current illicit drug use was almost 9 times higher among youths aged 12 to 17 who smoked cigarettes in the past month (47.8 percent) than it was among youths who did not smoke cigarettes in the past month (5.4 percent).
Past month illicit drug use also was associated with the level of past month alcohol use. Among youths aged 12 to 17 in 2006 who were heavy drinkers (i.e., drank five or more drinks on the same occasion [i.e., at the same time or within a couple of hours of each other] on each of 5 or more days in the past 30 days), 57.6 percent also were current illicit drug users, which was higher than among nondrinkers (4.8 percent).

Driving Under the Influence of Illicit Drugs

In 2006, there were 10.2 million persons aged 12 or older who reported driving under the influence of illicit drugs during the past year. This corresponds to 4.2 percent of the population aged 12 or older, similar to the rate in 2005 (4.3 percent), but lower than the rate in 2002 (4.7 percent). In 2006, the rate was highest among young adults aged 18 to 25 (13.0 percent).

Source of Prescription Drugs

Nonmedical users of prescription-type psychotherapeutic drugs are asked questions regarding how they obtained the drugs they recently used nonmedically. In both 2005 and 2006, over half of the nonmedical users of prescription-type pain relievers, tranquilizers, stimulants, and sedatives said they obtained the drugs they used most recently "from a friend or relative for free." A follow-up question added in 2006 asked these respondents where their friend or relative had obtained the drugs.
Among persons aged 12 or older who used pain relievers nonmedically in the past 12 months, 55.7 percent reported in 2006 that they got the pain relievers they most recently used from a friend or relative for free. Another 9.3 percent bought the drugs from a friend or family member. Around one fifth (19.1 percent) reported they got the drugs from just one doctor. Only 3.9 percent got the pain relievers from a drug dealer or other stranger, and only 0.1 percent reported buying the drug on the Internet.
In 80.7 percent of the cases where nonmedical users of prescription pain relievers obtained the drugs from a friend or relative for free, the individuals indicated that their friend or relative had obtained the drugs from just one doctor. Only 1.6 percent reported that the friend or relative had bought the drug from a drug dealer or other stranger.
In 2006, over half (53.6 percent) of past year methamphetamine users reported that they obtained the methamphetamine they used most recently from a friend or relative for free. Another 21.4 percent bought it from a friend or relative. Around one in five users (21.1 percent) bought it from a drug dealer or other stranger.

3. Alcohol Use

The National Survey on Drug Use and Health (NSDUH) includes questions about the recency and frequency of consumption of alcoholic beverages, such as beer, wine, whiskey, brandy, and mixed drinks. An extensive list of examples of the kinds of beverages covered is given to respondents prior to the question administration. A "drink" is defined as a can or bottle of beer, a glass of wine or a wine cooler, a shot of liquor, or a mixed drink with liquor in it. Times when the respondent only had a sip or two from a drink are not considered to be consumption. For this report, estimates for the prevalence of alcohol use are reported primarily at three levels defined for both males and females and for all ages as follows:

Current (past month) use - At least one drink in the past 30 days (includes binge and heavy use).

Binge use - Five or more drinks on the same occasion (i.e., at the same time or within a couple of hours of each other) on at least 1 day in the past 30 days (includes heavy use).

Heavy use - Five or more drinks on the same occasion on each of 5 or more days in the past 30 days.

Slightly more than half of Americans aged 12 or older reported being current drinkers of alcohol in the 2006 survey (50.9 percent). This translates to an estimated 125 million people, which is similar to the 2005 estimate of 126 million people (51.8 percent).
More than one fifth (23.0 percent) of persons aged 12 or older participated in binge drinking at least once in the 30 days prior to the survey in 2006. This translates to about 57 million people. The rate in 2006 is similar to the rate in 2005 (22.7 percent).
In 2006, heavy drinking was reported by 6.9 percent of the population aged 12 or older, or 17 million people. This percentage is similar to the rate of heavy drinking in 2005 (6.6 percent).

Age

In 2006, rates of current alcohol use were 3.9 percent among persons aged 12 or 13, 15.6 percent of persons aged 14 or 15, 29.7 percent of 16 or 17 year olds, 51.6 percent of those aged 18 to 20, and 68.6 percent of 21 to 25 year olds (Figure 3.1). Among older age groups, the prevalence of alcohol use decreased with increasing age, from 63.5 percent among 26 to 29 year olds to 48.0 percent among 60 to 64 year olds and 38.4 percent among people aged 65 or older.

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Figure 3.1 Current, Binge, and Heavy Alcohol Use among Persons Aged 12 or Older, by Age: 2006

Figure 3.1

Rates of binge alcohol use in 2006 were 1.5 percent among 12 or 13 year olds, 8.9 percent among 14 or 15 year olds, 20.0 percent among 16 or 17 year olds, 36.2 percent among persons aged 18 to 20, and 46.1 percent among those aged 21 to 25. The rate peaked at ages 21 to 23 (49.3 percent at age 21, 48.9 percent at age 22, and 47.2 percent at age 23), then decreased beyond young adulthood from 34.2 percent of 26 to 34 year olds to 18.4 percent of persons aged 35 or older.
The rate of binge drinking was 42.2 percent for young adults aged 18 to 25. Heavy alcohol use was reported by 15.6 percent of persons aged 18 to 25. These rates are similar to the rates in 2005 (41.9 and 15.3 percent, respectively).
Persons aged 65 or older had lower rates of binge drinking (7.6 percent) than adults in other age groups. The rate of heavy drinking among persons aged 65 or older was 1.6 percent.
The rate of current alcohol use among youths aged 12 to 17 was 16.6 percent in 2006. Youth binge and heavy drinking rates were 10.3 and 2.4 percent, respectively. These rates are essentially the same as the 2005 rates (16.5 percent, 9.9 percent, and 2.4 percent, respectively).

Underage Alcohol Use

In 2006, about 10.8 million persons aged 12 to 20 (28.3 percent of this age group) reported drinking alcohol in the past month. Approximately 7.2 million (19.0 percent) were binge drinkers, and 2.4 million (6.2 percent) were heavy drinkers. These figures have remained essentially the same since the 2002 survey.
More males than females aged 12 to 20 reported current alcohol use (29.2 vs. 27.4 percent, respectively), binge drinking (21.3 vs. 16.5 percent), and heavy drinking (7.9 vs. 4.3 percent) in 2006 (Figure 3.2).

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