Substance use disorders negatively affect global disease burden. Effective preventive interventions are available, but whether they provide value for money is unclear.

This review looks at the cost-effectiveness evidence of preventive interventions for cannabis use, opioid misuse and illicit drug use.

Literature search was undertaken in Medline, CINAHL, PsycINFO, EconLit through EBSCOhost and EMBASE, up to May 2021. Grey literature search was conducted as supplement. Studies included were full economic evaluations or return-on-investment (ROI) analyses for preventing opioid misuse, cannabis and illicit drug use. English-language restriction was used. Outcomes extracted were incremental cost-effectiveness ratios (ICER) or ROI ratios, with costs presented in 2019 United States dollars. Quality was assessed with the Drummond checklist.

Eleven full economic evaluation studies were identified from 5674 citations, with all studies conducted in high-income countries. Most aimed to prevent opioid misuse (n = 4), cannabis (n = 3) or illicit drug use (n = 5). Modelling was the predominant methodology (n = 7). Five evaluated school-based universal interventions targeting children and adolescents (aged <18 years). Five cost–benefit studies reported cost-savings. One cost-effectiveness and two cost–utility analysis studies supported the cost-effectiveness of interventions, as ICERs fell under prespecified value-for-money thresholds.

There are limited economic evaluations of preventive interventions for opioid misuse, cannabis and illicit drug use. Family-based intervention (ParentCorps), school-based interventions (Social and Emotional Training and Project ALERT) and a doctor's programme to assess patient risk of misusing narcotics (‘the Network System to Prevent Doctor-Shopping for Narcotics’) show promising cost-effectiveness and warrant consideration.

Alcohol use is a leading risk factor for death and disability worldwide.

We conducted a systematic review on the cost-effectiveness evidence for interventions to prevent alcohol use across the lifespan.

Electronic databases (EMBASE, Medline, PsycINFO, CINAHL and EconLit) were searched for full economic evaluations and return-on-investment studies of alcohol prevention interventions published up to May 2021. The methods and results of included studies were evaluated with narrative synthesis, and study quality was assessed by the Drummond ten-point checklist.

A total of 69 studies met the inclusion criteria for a full economic evaluation or return-on-investment study. Most studies targeted adults or a combination of age groups, seven studies comprised children/adolescents and one involved older adults. Half of the studies found that alcohol prevention interventions are cost-saving (i.e. more effective and less costly than the comparator). This was especially true for universal prevention interventions designed to restrict exposure to alcohol through taxation or advertising bans; and selective/indicated prevention interventions, which involve screening with or without brief intervention for at-risk adults. School-based interventions combined with parent/carer interventions were cost-effective in preventing alcohol use among those aged under 18 years. No interventions were cost-effective for preventing alcohol use in older adults.

Alcohol prevention interventions show promising evidence of cost-effectiveness. Further economic analyses are needed to facilitate policy-making in low- and middle-income countries, and among child, adolescent and older adult populations.