Interventions to Prevent Illicit and Nonmedical Drug Use in Children, Adolescents, and Young Adults: Updated Systematic Evidence Review for the U.S. Preventive Services Task Force [Internet]

Importance Illicit and nonmedical drug use is common in adolescents and young adults, and increases the risk of injury, death, and other harmful outcomes. Objective To systematically review the benefits and harms of primary care-relevant interventions to prevent illicit and nonmedical drug use in children, adolescents, and young adults to inform the United States Preventive Services Task Force. Data Sources MEDLINE, PubMED, PsycINFO, and the Cochrane Central Register of Controlled Trials; references of relevant publications, government Web sites. Study Selection English-language randomized and nonrandomized clinical trials of behavioral counseling interventions to prevent illicit and nonmedical drug use among young people with no history of regular or problematic illicit drug use. Data Extraction and Synthesis Two investigators independently reviewed abstracts and full-text articles, then we extracted data from studies rated as fair- and good-quality, based on predetermined criteria. We extracted illicit drug use outcomes as well as health, social, legal, other behavioral (e.g., use of other substances, other risky behaviors), and harms-related outcomes. Random-effects meta-analysis was used to estimate the benefits of the interventions. Strength-of-evidence ratings were made based on consistency, precision, study quality, and evidence of reporting bias, taking into account the size of the evidence base and other noted limitations. Results We identified 29 trials (N=18,353) that met our inclusion criteria. Twenty-six of the trials focused on nonpregnant youth covering ages 10 through 24 years, collectively, and are referred to as “general prevention” trials. Health outcomes were reported in 16 of the general prevention trials, but no single outcome was widely reported and most showed no group differences. Some of the general prevention interventions reduced illicit and nonmedical drug use; however, results were inconsistent across the body of literature and the pooled effect did not show a statistically significant association with illicit drug use (pooled SMD=-0.08 [95% CI, −0.16 to 0.001], k=24 [from 23 studies], n=12,801, I2=57.0%), pooling a wide range of outcomes (e.g., any use, frequency of use, score on a continuous use scale). Among 26 general prevention trials reporting any use of either cannabis or all drugs, the absolute percent of participants using illicit drugs ranged from 2.3 to 38.6 percent in the control groups and 2.4 to 33.7 percent in the intervention groups at followup ranging from 3 to 32 months, and the median absolute risk difference between groups was −2.8 percent, favoring the intervention group (range, −11.5% to +14.8%). When examining the change in total number of times illicit drugs were used in the previous 3 months, the pooled mean difference between groups was −0.21 times (95% CI, −0.44 to 0.02, k=11, n=3651, I2=51.0%). The remaining three trials provided an intensive, multitarget, perinatal home-visiting intervention to pregnant Native American youth (Family Spirit intervention). Only one of the Family Spirit trials (the largest, best-quality of the three) found a reduction in depression, externalizing behaviors, and illicit drug use, only at the last (38-month) followup for most outcomes. Across all 29 trials, only one trial reported on harms, a Family Spirit trial, and found no group differences, after controlling for contact time. Two general prevention trials reported statistically significantly higher illicit drug use in the intervention group at followup. Limitations Health outcomes were sparsely reported, and drug-related outcomes were very heterogeneous, including any illicit use, frequency of use, and use scores for either cannabis only or all illicit drugs combined. We did not include general prevention interventions that did not appear to have drug-specific content and that did not report illicit drug use outcomes. This led to the exclusion of programs including children younger than the age of 10, since trials in young children did not target drug use specifically and typically reported behavioral and academic outcomes rather than illicit drug use outcomes. Conclusions We found low strength of evidence on the benefits of behavioral counseling interventions to prevent illicit and nonmedical substance use in young people due to inconsistency and imprecision of findings. Health, social, and legal outcomes were sparsely reported and few showed improvement. Some interventions were associated with reductions in illicit and nonmedical drug use; however, others showed no benefit and two found paradoxical increases in use.