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National Survey on Drug Use and Health Marijuana Use in Substate Areas
June 16, 2005

Marijuana Use in Substate Areas

In Brief

  • By combining three years of data from the NSDUH, substate estimates of substance use can be produced

  • In 1999 to 2001, past month use of marijuana varied from lows of 2.3 percent in Northwest Iowa and 2.6 percent in Southern Texas to highs of 12.2 percent in Boston, Massachusetts and 10.3 in Boulder, Colorado

  • Of the 15 substate areas with the highest rates of past month marijuana use in the United States, 5 were in Massachusetts, 3 were in California, and 2 were in Colorado
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Use of illicit drugs, alcohol, and cigarettes is known to vary across States.1 Estimates for these variations are derived from the National Survey on Drug Use and Health (NSDUH), which asks persons aged 12 or older to report on their use of cigarettes, alcohol, and illicit drugs in the past year and in the past month. Illicit drugs include marijuana/hashish, cocaine (including crack), inhalants, hallucinogens, heroin, or prescription-type drugs used nonmedically. This issue of The NSDUH Report uses data from the combined 1999 to 2001 NSDUH surveys to present estimates of past month use of marijuana for 331 geographic areas within the 50 States and the District of Columbia. The marijuana data are extracted from a more extensive report that includes substate estimates of 12 substance use measures, Substate Estimates from the 1999-2001 National Surveys on Drug Use and Health, available at http://samhsa.gov/data/substateList.cfm
Methodology

Estimates presented in this report and the full report are based on a small area estimation (SAE) procedure in which NSDUH data at the substate level are combined with local-area county and Census block group/tract-level data from the area to provide more precise estimates. The same methodology is used to produce State estimates from NSDUH.1 Substate areas were developed collaboratively between staff at the Substance Abuse and Mental Health Services Administration (SAMHSA) and State substance abuse treatment representatives, with the States making the final decision on the geographic boundaries. In most States, the substate areas are defined in terms of counties or groups of counties; in some States, the areas are defined in terms of Census tracts. For each of the 12 measures presented in the complete report, estimates for the substate areas were ranked from lowest to highest and grouped into seven categories.2

Figure 1. Marijuana Use in Past Month among Persons Aged 12 or Older, by Substate Region: Percentages, Annual Averages Based on 1999, 2000, and 2001 NSDUH Data
Figure 1. Marijuana Use in Past Month among Persons Aged 12 or Older, by Substate Region: Percentages, Annual Averages Based on 1999, 2000, and 2001 NSDUH Data
Marijuana Use at the Substate Level

Nationally, an average of 5.1 percent of persons aged 12 or older reported using marijuana in the past month from 1999 through 2001. Past month marijuana use ranged from a low of 2.3 percent in Northwest Iowa to a high of 12.2 percent in Boston, Massachusetts (Figure 1).3 Of the 15 substate areas with the highest rates of past month marijuana use in the United States, 5 were in Massachusetts, and 4 of the 15 areas with the lowest rates were in Iowa. Three areas in California and two areas in Colorado also ranked in the top 15. In some States, there was a large variation in the percentage using marijuana in the past month depending on the substate area. For example, rates in California ranged from a low of 4.9 percent in Region 14 (Orange County) and Region 11 (Los Angeles County) to a high of 9.2 percent in Region 4 (Marin, San Mateo, and San Francisco Counties). Rates in Colorado ranged from 6.3 percent (Regions 1 and 4, covering 27 counties in the eastern part of the State) to 10.3 percent in Region 7 (Boulder County).

Complete Report

The full report with estimates for 12 measures of substance use is only available online at http://samhsa.gov/data/substate2k5/toc.cfm. In addition to past month marijuana use, estimates are presented for 11 other measures of substance use among persons aged 12 or older: past month use of any illicit drug, incidence rate of marijuana use, past month use of any illicit drug other than marijuana, past year use of cocaine, past month use of alcohol, past month binge use of alcohol, past month use of tobacco, past month use of cigarettes, perceptions of great risk of smoking marijuana once a month, perceptions of great risk of having five or more drinks of an alcoholic beverage once or twice a week, and perceptions of great risk of smoking one or more packs of cigarettes a day. Also included in the report are national maps for all 12 measures for the 331 substate areas, detailed tables for the substate areas, and definitions and population counts for the substate areas. The complete report gives a detailed description of the methodology used to generate the model-based estimates.

End Notes
  1. Wright, D., & Sathe, N. (2005). State estimates of substance use from the 2002-2003 National Surveys on Drug Use and Health (DHHS Publication No. SMA 05-3989, NSDUH Series H-26). Rockville, MD: Substance Abuse and Mental Health Services Administration, Office of Applied Studies.

  2. In the national maps, substate areas are divided into thirds. The third with the lowest prevalence rates are presented in blue (ranging from dark to light blue), the third with the highest prevalence rates are in red (ranging from light to dark red), and the remainder (the middle third) are in white. The darkest shades represent the 15 areas with the lowest (dark blue) and highest (dark red) prevalence rates. The medium shades represent the next 30 lowest and highest areas, and the light shades designate the next 65 lowest and highest areas.

  3. The Boston substate area includes primarily Boston City, specifically all of Suffolk County and some tracts in Norfolk County. The 95 percent prediction interval for the substate area is from 9.3 to 15.7 percent.

Figure Notes

For definitions of substate regions, see section D at http://samhsa.gov/data/substateList.cfm

Source: SAMHSA, 1999-2001 NSDUH.
The National Survey on Drug Use and Health (NSDUH) is an annual survey sponsored by the Substance Abuse and Mental Health Services Administration (SAMHSA). Prior to 2002, this survey was called the National Household Survey on Drug Abuse. The 1999 to 2001 data are based on information obtained from 207,399 persons aged 12 or older. The survey collects data by administering questionnaires to a representative sample of the population through face-to-face interviews at their place of residence.

The NSDUH Report is prepared by the Office of Applied Studies (OAS), SAMHSA, and by RTI International in Research Triangle Park, North Carolina. (RTI International is a trade name of Research Triangle Institute.)

Information and data for this issue are based on the following publication and statistics:

Office of Applied Studies. (2005). Substate estimates from the 1999-2001 National Surveys on Drug Use and Health. Rockville, MD: Substance Abuse and Mental Health Services Administration. [Available online at http://samhsa.gov/data/substate2k5/toc.cfm]

 

The NSDUH Report (formerly The NHSDA Report) is published periodically by the Office of Applied Studies, Substance Abuse and Mental Health Services Administration (SAMHSA). All material appearing in this report is in the public domain and may be reproduced or copied without permission from SAMHSA. Additional copies of this report or other reports from the Office of Applied Studies are available on-line: http://www.oas.samhsa.gov. Citation of the source is appreciated. For questions about this report please e-mail: shortreports@samhsa.hhs.gov.

This page was last updated on May 16, 2008.