Because of the vast and growing literature on substance use prevention and treatment in young people, we did a systematic review of reviews in two stages. First, in May, 2015, we did an initial exploratory search in the Project Cork bibliographies, PubMed Clinical Queries, and Scopus to refine our search strategy. Second, we searched MEDLINE, MEDLINE-in-process, Embase, PsycINFO, and the Cochrane Database of Systematic Reviews for reviews published in English between Jan 1, 1990, and April 23,
SeriesPrevention, early intervention, harm reduction, and treatment of substance use in young people
Introduction
Substance use in young people is an important public health concern. As noted in the first paper of this Series by Degenhardt and colleagues,1 adolescence is the peak period for initiation of substance use, which imparts large health burdens in this age group. Young people (defined here as aged 10–24 years)2 are a broad and dynamic group that includes school-aged children, teenagers, and young adults. As a result, the responses to substance use in young people will differ substantially depending on their age, stage of life, level of substance use, and their socioenvironmental context.
In thinking about the responses to substance use in young people, one must first take into account the differences to the adult population that young people experience during this period of rapid growth and development. These include the rapid physiological development during puberty,3 which can affect cognitive reasoning, emotional regulation, and risk taking. In this respect, young people are progressing through a period of their lives that has both tremendous opportunity, but also much risk with respect to substance use, given the state of heightened emotion and the importance of peers during adolescence.4 Additionally, young people are making developmental and life milestones such as the end of education, transition to a career, and a move towards independence including new intimate relationships and, in some cases, becoming a parent.
Second, given that young people are at a different stage of life to the adult population, the focus of responses to substance use is often heavily on prevention, early intervention, and reduction of harms in those who have begun to use substances rather than intensive treatment of dependent users. Third, most young people using substances, even heavy use, do not yet have established drug dependence (particularly in the teenage years), which has broad implications on the role of drug treatment services and the applicability of treatment approaches that have good evidence in adults. Finally, the platforms through which interventions can be delivered in this age group are unique. Educational settings can be a good fit to deliver interventions and mobile and online interventions might be more appealing and have greater uptake in this age group than older age groups.
In this Series paper, we review the responses to substance use in young people, building on the epidemiology of substance use in young people,1 and the unique developmental and contextual risks of substance use and the resulting harms.3 We critically assess evidence on the efficacy of various intervention approaches and how these differ according to age, level of substance use, and socioenvironmental context. These approaches range from macro-level population-based interventions (eg, legislation, regulation, and law enforcement) to individual-level interventions (eg, early intervention, reduction of harms in young people who are using substances who are at risk of acute adverse effects, and treatment of problematic or dependent substance use). The type and targets of interventions will vary according to age and level of substance use. For example, school-based approaches for young people who might not have started using substances will differ from approaches used for college students who might have begun their transition to independent living and could be experimenting with substances. Similarly, approaches will differ to target young adults who live independently from their families of origin, and might have begun to develop heavy patterns of substance use, including dependence. We judge whether intervention approaches need to be structured differently for young people, and the important issues of treatment setting and confidentiality for those younger than 18 years.
Our primary sources of evidence were systematic reviews of randomised controlled trials or quasi-experimental designs that used a control condition. However, if no such evidence was available or the completion of randomised controlled trials was impractical, unethical, or politically difficult, we assessed evidence from natural experiments (eg, observational studies), before-and-after studies, and time-series analyses. Additionally, we consulted other reviews5, 6, 7, 8 and searched for empirical studies in areas in which no reviews were found.
Section snippets
Framework for interventions
Table 1 and the figure summarise the logic of the major interventions to prevent young people initiating substance use, to intervene early, and to reduce harms or treat substance use problems. Prevention interventions are typically population-level interventions and can have different aims (table 1). They could aim to reduce young people's interest in using substances, limit availability of substances to make them more difficult to obtain or consume, or use criminal or other social sanctions to
Prohibition of the use of controlled substances
Non-medical use of cannabis, opioids, amphetamines, and cocaine is prohibited in countries that have signed the UN Single Convention on Narcotic Drugs.83 Prohibition with severe criminal penalties for drug use remains controversial because only weak evidence is available to show that tough sanctions reduce criminal offending in general or drug use in particular.6 In the past 5–10 years, policy changes in Uruguay, Portugal, and the USA have permitted some examination of the potential effects of
Interventions with young people using substances: early intervention and harm reduction
Various interventions have been targeted at young people who have started using substances. These aim to reduce substance use, reduce risky patterns of substance use, and reduce the harms that might arise from use. Although the rationale for these early interventions is clear, evidence on their effectiveness is sparse and of low quality. Interventions that aim to reduce the adverse resulting effects of substance use (rather than reducing substance use per se) are often termed harm reduction
Treatment of problematic substance use and substance dependence
In this section we summarise interventions targeting problematic or dependent substance use in young people. A summary of the issues and available evidence of cost-effectiveness of these interventions is available in the appendix.
A range of issues need to be thought about by any services targeting this population of young people, irrespective of the specific interventions being applied (panel 4). These include stigma surrounding substance use, the attractiveness to use services by young people,
Discussion
Adolescence and young adulthood represent key periods during which substance use behaviours can become established. Therefore these are important periods in which to prevent these behaviours from occurring, reduce the escalation to heavy drug use, and intervene to address established problematic substance use. With evidence suggesting increasing use of substances in young people,1 a solid evidence base is essential to help decide the best response to these public health issues.
To improve the
Search strategy and selection criteria
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