Patient Population under Consideration
While the rate of illicit drug use in the U.S. is highest between the
ages of 18 to 20 years, more than 10% of adolescents aged 12 to17 are
known to use illicit drugs. The percentage of adults who regularly use
illicit drugs decreases steadily with age. About 5% of pregnant women
report using illicit drugs within the past month.
Patterns of Drug Use
Marijuana is the most commonly used illicit drug in the United States,
with about 6% of the population age 12 and older admitting to use within
the past month. While cocaine is the second most commonly used illicit
drug, it is used by less than 1% of the population. Only a small
minority of Americans use hallucinogens, inhalants, heroin, or illicitly
manufactured methamphetamine, although the potential for abuse of or
dependence on these substances is high. Illicit (non-medical) use of
prescription-type drugs, categorized as pain relievers, tranquilizers,
stimulants, and sedatives, is a growing health problem in the U.S.
Screening Tests
While clinicians should be alert to the signs and symptoms of illicit
drug use in patients, the added benefit of screening asymptomatic
patients in primary care practice remains unclear. Toxicologic tests of
blood or urine can provide objective evidence of drug use, but such
tests do not distinguish between occasional users and those who are
impaired by drug use. A few brief, standardized questionnaires have been
shown to be valid and reliable in screening adolescent and adult
patients for drug use/misuse. However, the clinical utility of these
questionnaires is uncertain. The reported positive predictive values are
variable and at best 83% when the questionnaires are applied in a
general medical clinic. Moreover, the feasibility of routinely
incorporating the questionnaires into busy primary care practices has
yet to be assessed. The validity, reliability, and clinical utility of
standardized questionnaires in screening for illicit drug use during
pregnancy have not been adequately evaluated.
Treatment
Although drug-specific pharmacotherapy (e.g., buprenorphine for opiate
abuse) and/or behavioral interventions (e.g., brief motivational
counseling for cannabis misuse) have been proven effective in reducing
illicit drug use in the short term, the longer-term effects of
treatment on morbidity and mortality have been inadequately evaluated.
Moreover, these treatments have been studied almost exclusively in
individuals who have already developed medical, social, or legal
problems due to drug use, and their effectiveness in individuals
identified through screening remains unclear. In all but one trial,
treatment was delivered outside the primary care setting, often in
specialized treatment facilities. More evidence is needed on the
effectiveness of office-based treatments for illicit drug
use/dependence.
Other Approaches to Prevention
While interventions to prevent or reduce illicit drug use have been
proposed for use in schools and sites of employment, evidence assessing
preventive measures delivered in settings other than primary care
practice was outside the scope of the USPSTF review. However, the
Centers for Disease Control and Prevention's (CDC) Task Force on
Community Preventive Services has announced plans to assess the
effectiveness of selected population-based interventions for preventing
or reducing abuse of drugs (other than tobacco and alcohol) and to make
recommendations based on these findings.