State Estimates of Substance Use from the 2002 NSDUH

2002 State Estimates of Substance Use

5. Substance Dependence, Abuse, and Treatment Need

An estimated 22.0 million Americans aged 12 or older in 2002 were classified with dependence on or abuse of either alcohol or illicit drugs (Office of Applied Studies [OAS], 2003b). Most of these persons (14.9 million) were dependent on or abused alcohol only. Another 3.2 million were dependent on or abused both alcohol and illicit drugs, while 3.9 million were dependent on or abused illicit drugs but not alcohol. The dependence or abuse status is based on the criteria specified in the 4^th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) (American Psychiatric Association [APA], 1994).

5.1. Alcohol Dependence or Abuse

Nationally, 7.7 percent of the population aged 12 or older was classified with dependence on or abuse of alcohol in the past year (Table A.13). Persons aged 18 to 25 had the highest rate of alcohol dependence or abuse (17.7 percent).

State estimates for 2002 for persons aged 12 or older ranged from 6.3 percent in Alabama to 10.2 percent in Nebraska. States in the highest fifth tended to be mostly Western (Colorado, Montana, New Mexico, and Wyoming) or Midwestern (Nebraska, North Dakota, and South Dakota) (Figure 5.1). Five States in the lowest fifth were in the South (Alabama, Florida, Mississippi, Tennessee, and West Virginia).

In the 12 to 17 age group, the estimated percentage of those identified as having an alcohol abuse or dependence problem ranged from 3.1 percent in the District of Columbia to 9.9 percent in Montana. Among persons aged 18 to 25, the lowest percentage was found in California (13.4 percent) and the highest State percentage was in Nebraska (27.2 percent). Only Montana and Nebraska were in the highest fifth for the 12 to 17, 18 to 25, and 26 or older age groups (Figures 5.2 to 5.4).

In 2002, the percentage of persons estimated to be dependent on alcohol in the past year was about 45 percent of those who were determined to be dependent on or abusing alcohol in the past year (Tables A.13 and A.14). State estimates for alcohol dependence for persons aged 12 or older ranged from 2.8 percent in Pennsylvania to 5.2 percent in the District of Columbia (Table A.14). Seven of the States in the top fifth for dependence on or abuse of alcohol also could be found in the top fifth for dependence on alcohol for persons aged 12 or older: Colorado, District of Columbia, Nebraska, New Mexico, North Dakota, Rhode Island, and South Dakota (Figures 5.1 and 5.5). Of the remaining three States in the top fifth for dependence on alcohol, Michigan ranked in the second fifth for alcohol dependence or abuse, Louisiana in the middle fifth, and South Carolina in the next-to-lowest fifth. The highest rates for alcohol dependence occurred in the 18 to 25 age group, with Rhode Island having the highest rate—about 12.0 percent.

5.2. Illicit Drug Dependence or Abuse

Nationally in 2002, about 3.0 percent of persons aged 12 or older were dependent on or had abused illicit drugs in the past year (Table A.15). The District of Columbia had the highest rate of illicit drug abuse or dependence for persons aged 12 or older (4.3 percent), and Kansas had the lowest rate (2.5 percent). Most of the States in the highest fifth were in the West (six States) (Figure 5.9). Only four of the States in the top fifth for illicit drug dependence or abuse also were in the top fifth for alcohol dependence or abuse among persons aged 12 or older: District of Columbia, Montana, New Mexico, and Rhode Island (Figures 5.1 and 5.9). Rhode Island had the highest rate for illicit drug dependence or abuse among persons aged 18 to 25 (13.9 percent); Vermont had the highest rate among youths (8.8 percent). There were no States common to the highest fifth for all three age groups (12 to 17, 18 to 25, and 26 or older) (Figures 5.10 to 5.12).

The percentage of persons estimated to be dependent on illicit drugs in the past year was about 65 percent of those who were estimated to be dependent on or abused illicit drugs in the past year (Tables A.15 and A.16). State estimates for illicit drug dependence for persons aged 12 or older ranged from 1.5 percent in Hawaii to 3.3 percent in the District of Columbia. The highest rates of illicit drug dependence were among persons aged 18 to 25, with the highest rate in Rhode Island—10.0 percent.

There was a slight relationship between high rates of past year illicit drug dependence and high rates of past year cocaine use for persons aged 12 or older at the State level. Four States were ranked among the highest for both measures: District of Columbia, Massachusetts, Ohio, and Rhode Island (Figures 2.21 and 5.13).

5.3. Alcohol or Illicit Drug Dependence or Abuse

The national rate for past year dependence on or abuse of alcohol or illicit drugs among persons aged 12 or older was about 9.4 percent (Table A.17). When examining dependence on or abuse of alcohol or illicit drugs at the State level, the States with high rates for alcohol dependence or abuse tended to dominate the top fifth for alcohol and illicit drug dependence or abuse combined because alcohol accounts for the vast majority of substance dependence or abuse.

For those aged 12 or older, the State percentages ranged from a low of 7.6 percent in Alabama to a high of 12.7 percent in the District of Columbia for past year dependence on or abuse of illicit drugs or alcohol. Nine out of ten States in the top fifth for dependence on or abuse of illicit drugs or alcohol for persons aged 12 or older also were in the top fifth for dependence on or abuse of alcohol alone (Figures 5.1 and 5.17).

The prevalence rate for past year dependence on or abuse of any illicit drug or alcohol among persons aged 18 to 25 was almost 3 times as high as that for all persons aged 12 or older. Rhode Island's rate of 32.0 percent was the highest among States for this age group. Many of the States in the top fifth both for the 18 to 25 and for the 12 to 17 age groups were the same as those in the top fifth for all persons aged 12 or older (Figures 5.17 to 5.19).

2002 State Estimates of Substance Use

5.4. Needing But Not Receiving Treatment for Illicit Drug Problems

The definition of a person needing but not receiving treatment for an illicit drug problem is that he or she meets the criteria for abuse of or dependence on illicit drugs according to the DSM-IV, but has not received specialty treatment for an illicit drug problem in the past year. Specialty treatment is treatment received at a drug and alcohol rehabilitation facility (inpatient or outpatient), hospital (inpatient only), or mental health center.

It is important to note that the prevalence rate for needing but not receiving treatment for illicit drug problems was not calculated here by estimating one model for treatment need and another model for receipt of treatment, and then subtracting one from the other at the State level. The reason for this is that the percentage of persons receiving treatment is too small to estimate well. Instead, at the individual level, persons are designated as needing but not receiving treatment for an illicit drug use problem based on their meeting the criteria for treatment need and whether they received treatment for abuse of, or dependence on, illicit drugs in the past year. In general, the definitions of dependence, abuse, or treatment for alcohol or illicit drugs contain components that often overlap one another, and a researcher may be tempted to subtract them at the State level to obtain some missing component. Each measure is based on a different model, and subtraction can lead to erroneous results, such as a "negative" component.

New Mexico had the highest percentage of persons aged 12 or older needing but not receiving treatment for an illicit drug use problem in 2002 (3.5 percent) (Table A.18). The other States in the top fifth were mainly in the West (Alaska, Arizona, Montana, Nevada, Oregon, and Washington) or in the Northeast (Rhode Island and Vermont) (Figure 5.21). California had the largest total number of persons aged 12 or older needing but not receiving treatment for an illicit drug use problem, approximately 819,000, or about 13.0 percent of the total for the Nation (see http://www.oas.samhsa.gov/states.htm).

Persons aged 12 to 25 accounted for almost 60 percent (57.8 percent) of the total number of persons needing but not receiving treatment for an illicit drug use problem. However, that group represented only 23 percent of the total population aged 12 or older. The percentage of the total accounted for by persons aged 12 to 25 at the State level ranged from 44 percent in the District of Columbia to 72 percent in New Hampshire (Figures 5.21 to 5.23).

5.5. Needing But Not Receiving Treatment for Alcohol Problems

The definition of a person needing but not receiving treatment for an alcohol problem is that he or she meets the criteria for abuse of or dependence on alcohol according to the DSM-IV, but has not received specialty treatment for an alcohol problem in the past year. The percentage of persons aged 12 or older needing but not receiving treatment for alcohol problems (7.3 percent) was approximately 3 times larger than the corresponding percentage for persons with illicit drug problems (2.7 percent) (Tables A.18 and A.19). As with past month alcohol use, most of the States in the top fifth for all persons aged 12 or older were Northern States, with the exception of Arizona, District of Columbia, and New Mexico. Among persons aged 12 or older, 9 of the 10 top States for persons needing but not receiving treatment for alcohol problems also were ranked in the top fifth for alcohol dependence or abuse in that population (Figures 5.1 and 5.25). Young adults aged 18 to 25 reported the highest rates in the Nation, about 3 times higher than the other age groups. Nebraska, New Mexico, North Dakota, and South Dakota appeared in the top fifth for persons aged 12 or older, as well as in each of the three age subgroups (Figures 5.25 to 5.28). Of the 10 States ranked in the top fifth for persons aged 12 or older, 7 also were in top fifth for the 26 or older category, 8 also were in the top fifth among persons aged 18 to 25, and 6 also were in the top fifth among youths aged 12 to 17.