Secondary prevention interventions for young drug users: a systematic review of the evidence

Adolescence, Spring, 2005 by Lawrence Elliott, Linda Orr, Lynsey Watson, Andrew Jackson

INTRODUCTION

Drugs are commonly used by young people (Weinberg, Rahdert, Colliver, & Glantz, 1998; Bauman & Philayrath, 1999). With the exception of alcohol and tobacco, the most commonly used drug internationally is cannabis (Kingery, Alford, & Coggeshal], 1999). Lifetime prevalence of cannabis use is reported by at least one third of older adolescents in the United Kingdom (UK), New Zealand, and Switzerland (Bauman & Philayrath, 1999). Use of other drugs such as cocaine, stimulants, and inhalants are less common (Bauman & Philayrath, 1999; Kingery et al., 1999). There are important subgroups exposed to risks of drug use or problems associated with drug use. Between 0.4% and 3.3% of young drug users meet the criteria for abuse or dependence (Weinberg et al., 1998). It is likely that these groups of young people experience multiple problems (Lloyd, 1998). Coexisting problems include poor general health, poor family and social relations, dropping out of school, and psychiatric and psychological disorders such as depression and behavior problems (Weinberg et al., 1998; Swadi, 1999; Bray, Zarkin, Ringwalt, & Qi, 2000; Reid, Lynskey, & Copeland, 2000; Ferguson, Horwood, & Swain-Campbell, 2002).

A comprehensive range of services may be required to address the problems experienced by some young drug users (Crome, 1999; Gilvarry, 2000). These services might include a comprehensive needs assessment, family therapy, pharmacotherapy, outreach work, and residential care (Sloboda, 1999; Gilvarry, 2000). Other commentators discuss the possibility of embedding drugs services within existing health and social care agencies (Lloyd, 1998). These interventions are often advocated on the basis of expert opinion or selective review of the scientific literature. The extent to which these views are fully supported by the scientific literature is unclear.

The UK government's ten-year drug strategy published in 1998, and subsequently the Scottish Executive strategy published in 1999, set out to prevent drug use and improve access to drugs services for young people, including those up to the age of 16 years (Great Britain Cabinet Office, 1998; Scottish Office, 1999). The Effective Interventions Unit, Scottish Executive, commissioned the authors to undertake a review of the scientific evidence concerning the effectiveness of drugs interventions for young people, particularly those 16 years of age and under. The review would help inform the key principles and core models for service provision for young people. A final report was expected within a six-month period. The reason for the short time period was to fit the policy-making schedule.

It is against this background that the present review was conducted. The aim is to identify, critically appraise, and synthesize the international scientific evidence on the effectiveness of secondary prevention interventions for young drug users. The key questions are, How effective are secondary prevention interventions in: (1) reducing drug use among young users? (2) improving the psychological well-being of young drug users? and (3) improving the family and social relations of young drug users? The review also comments on the coverage of the current research and makes recommendations for service provision and research.

METHOD

Inclusion Criteria

Population. The following studies are included: those conducted with young drug users 16 years of age or under; studies that do not report the age of their subjects, preferring instead to use terms such as "adolescents" or "young people"; and studies concerned with older age groups that contain individuals of 16 years or less.

Intervention outcomes. Interventions assessed by examining their impact on drug use or the psychological or social problems associated with drug use.

Type of drug. Nonprescribed drugs except alcohol and tobacco.

Time period, publication type, and language. Primary and secondary research (systematic reviews) published in English between 1990 and 2001 were included. A cut-off point of 1990 was used because most primary studies of drug interventions for young people conducted before 1990 have been found to be of poor methodological quality (Williams & Chang, 2000). This view is also supported in a recent review of reviews of school drug education (McBride, 2002).

Study designs. Only experimental, quasi-experimental, and controlled observational studies are included.

Exclusion Criteria

The following studies are excluded: studies that focus solely on primary drug prevention (for example, drug awareness campaigns, drug education programs, mass media campaigns, government legislation, socioeconomic interventions); interventions focusing solely on alcohol or tobacco; noncontrolled studies (for example, cross-sectional, single sample before-and-after designs, single case studies, and expert opinion); and primary papers already included in accepted reviews.

Publication Sources

The following electronic libraries were searched for relevant publications: MIMAS Web of Science (science and social science indexes); Medline; Cochrane Library (including reviews and primary papers); Caredata; BIDS; ASSIA. The following sources were also searched: Department of Health, Health Technology Assessment Program (UK); Department of Health, National Research Register (UK); NHS Centre for Reviews Dissemination Database of Abstracts of Reviews Effects (DARE) and Health Technology Assessment Database (UK); The Health Development Agency (UK); Health Education Board for Scotland (HEBS); National Institute on Drug Abuse (NIDA) (USA); Drug and Alcohol Findings (UK). Sixty-three research experts, identified from the electronic and database searches, were contacted by letter and asked to provide a list of published and unpublished studies (1990-2001) which they considered to be of relevance to the topic area; 39 (62%) replied.