2.1 Measurement of Substance Use, Dependence, and Need for Treatment

The NHSDA includes a comprehensive battery of items covering licit and illicit substance use for the past month. Respondents are asked to indicate any use in the past month of: alcohol, cigarettes, marijuana, any illicit drug, and illicit drugs other than marijuana. Illicit drugs include marijuana, hashish, cocaine (including crack), inhalants, hallucinogens (including PCP and LSD), heroin, and the nonmedical use of a prescription psychotherapeutic.

The following NHSDA questionnaire items, called "recency" items, were used to determine past-month substance use. Respondents who reported that their most recent use of the specified substance occurred within the 30-day period preceding the interview were classified as having used the substance during the past month.
 

· Alcohol: "Think about the last time you drank any type of alcoholic beverage. How long has it been since you last drank an alcoholic beverage?"

· Cigarettes: "How long has it been since you last smoked a cigarette?"

· Marijuana: "How long has it been since you last used marijuana or hashish?"

· Any illicit drug use or illicit drugs other than marijuana: "How long has it been since you last used [name of drug]?"
 

In order to evaluate nonmedical use of sedatives, tranquilizers, stimulants, and analgesics, these items included a qualifying statement indicating that the substance was "not prescribed for you, or that you took only for the experience or feeling it caused."

Measures of substance dependence and need for substance abuse treatment were developed to identify patterns of problem substance use. The NHSDA items used to assess dependence are based on diagnostic criteria from the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV-American Psychiatric Association, 1994). Respondents were asked to identify consequences and symptoms diagnostic of dependence for specific substances during the year preceding the interview. These reports were used to define dependence on alcohol and illicit drugs.

It is important to note that questions used to estimate dependence were changed slightly from 1994 to 1995. The questions used to estimate dependence in 1994 were designed to approximate five of the seven DSM-IV criteria, while the questions used to estimate dependence beginning in 1995 were developed to approximate six of the criteria. In 1994, if three of five DSM-IV dependency criteria were indicated for a specific substance in the past year, respondents were classified as dependent. The 1994 dependence items included the following indicators:
 

· Built up a tolerance for the drug

· Used the drug more often than intended

· Wanted to cut down but unable to cut down

· Spent a month or more in the past year using or getting over the drug

· Indicated that the drug caused problems
 

In 1995 and again in 1996 the following six DSM-IV dependency criteria were used; if three of the six criteria were indicated for a specific substance in the past year, a respondent was classified as dependent:
 
· Built up a tolerance for the drug

· Used the drug more often than intended

· Wanted to cut down or tried, but found could not

· Spent a month or more in the past year getting, using, or getting over the drug

· Drug reduced important activities

· Drug caused emotional problems or health problems
 

In spite of the slightly different criteria for determining dependency, an investigation of the two measures indicate that they are comparable (Epstein and Gfroerer, 1996).

A measure of the probable need for illicit drug abuse treatment was also constructed following Epstein and Gfroerer (1996). A respondent was classified as in need of illicit drug abuse treatment if any of the following conditions were present in the past year:

· Dependence on any illicit drug

· Injection drug use

· Received treatment for drug use

· Daily use of marijuana

· Any heroin use

· Weekly use of psychotherapeutics, hallucinogens, inhalants, or cocaine
 

Past-month daily cigarette use was defined as smoking a cigarette on 25 or more of the past 30 days. Past-month "binge" alcohol use was defined as five or more drinks on the same occasion on one or more days during the past month. Drunk in the past year was defined as being drunk on three or more days.

This page was last updated on August 05, 2008.

SAMHSA, an agency in the Department of Health and Human Services, is the Federal Government's lead agency for improving the quality and availability of substance abuse prevention, addiction treatment, and mental health services in the United States.