Illicit drug use and abuse are serious problems among adolescents, adults, and pregnant women in the United States, and approximately 3.2% of the population age 12 and over meet criteria for a drug use disorder. Many individuals with drug use disorders have co-existing mental and physical health conditions.
To update the 1996 U.S. Preventive Services Task Force (USPSTF) recommendation on screening for drug misuse in primary care. The USPSTF previously concluded there was insufficient evidence to recommend for or against routine screening for drug misuse. This report describes a staged, systematic review that assessed whether the evidence for selected critical key questions is now sufficient for the USPSTF to make a recommendation on this topic.
Ovid MEDLINE, PsycINFO, and the Cochrane Database of Systematic Reviews, from 1994 through April 2006. Literature searches were supplemented with materials recommended by experts in the field and from reference lists in included articles.
We developed an analytic framework and identified five critical key questions (KQ) to examine evidence sufficiency in a causal chain linking primary care screening for drug misuse to treatment outcomes and longer-term health benefits of reductions in illicit drug use. We focused on the most prevalent and/or harmful substances: illicit opiates, cocaine, and cannabis. Using inclusion/exclusion criteria specific to each critical KQ, we reviewed a total of 4587 abstracts for all key questions and 41 full-text articles for inclusion regarding direct evidence of health benefits of drug screening programs in primary care, 127 articles for inclusion regarding drug misuse treatment outcomes in primary care-screened populations, and 79 articles for inclusion regarding improvements in health or mortality following reduction in or cessation of illicit drug use. Inclusion criteria for drug misuse treatment articles required randomized controlled or controlled trial designs comparing a treatment to placebo or minimal treatment control; comparative effectiveness trials were excluded. Using USPSTF and other published methods, we critically appraised studies using quality criteria specific to their design. We listed studies excluded from analysis and rationales for their exclusion.
We abstracted, critically appraised, and synthesized 28 articles meeting our criteria for all critical KQs. Abstracted elements were arrayed in evidence tables, using abstraction criteria specific to each KQ.
We qualitatively summarized the findings, with an emphasis on the best available evidence for each critical KQ and the overall coherence of the evidence. We found no evidence addressing the effects on health outcomes of screening in primary care settings to identify and treat drug misuse among asymptomatic individuals. We found no evidence that drug misuse treatment affects health outcomes among individuals screened in primary care, and found little qualifying evidence in non-screened (treatment-seeking) populations. We found fair to good evidence that various drug misuse treatments—including pharmacotherapies and behavioral interventions—effectively reduce opiate, cocaine, or marijuana misuse. All but one of the 17 included drug misuse treatment trials were conducted among treatment-seeking, instead of primary-care-screened populations. The exception was a brief motivational intervention that reduced cocaine and opiate use among primary care patients identified through screening for use of these substances. We found less consistent evidence of drug misuse treatment effects on social and legal outcomes, although behavioral counseling interventions for cannabis misuse appear to reduce cannabis-related problems. We found fair evidence that stopping or reducing drug misuse is related to reduced mortality and morbidity, although none of this evidence was derived from individuals screened for drug misuse in primary care settings.
Although many advances in drug misuse treatment have occurred during the past decade, the vast majority of trials have been conducted among treatment-seeking populations, and thus the relevance of outcomes from such studies is of uncertain applicability to asymptomatic primary care populations that could be screened for drug misuse. Evidence that reducing or stopping drug misuse is associated with improved health outcomes similarly derives from non-screened or treatment-seeking populations, and the generalizability of these findings to general primary care populations may be limited.
