Definition and research guide
This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.
Content available: 4 complete abstracts (1,122 words), 10 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.
Definition
The application of methods designed to reduce the risk of harm associated with certain behaviors without reduction in frequency of those behaviors. The risk-associated behaviors include ongoing and active addictive behaviors.
Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.
Also known as: Reduction, Harm; Harm Minimization; Minimization, Harm.
Where it fits in the MeSH classification
- Broader topics
- Behavior
- See also
- Risk
Research landscape
PubMed indexes 5,383 records tagged with the MeSH heading “Harm Reduction” (counts retrieved 2026-10-31). 2,268 of them (42.1%) were published from 2020 onward, and the busiest period so far is 2010-2019 with 2,288 records.
Reviews account for 678 records (12.6%) and meta-analyses for 36. Randomized controlled trials number 173 (3.2%) as a share of all records on the topic.
Show the data
| Period | Records |
|---|---|
| through 1999 | 0 |
| 2000-2009 | 899 |
| 2010-2019 | 2,288 |
| 2020 onward | 2,268 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 678 | 12.6% |
| Meta-analyses | 36 | 0.7% |
| Randomized controlled trials | 173 | 3.2% |
Method: PubMed query "Harm Reduction"[MeSH Terms] with publication-type and date filters, retrieved 2026-10-31.
Reading the evidence in psychiatry and psychology
Research on mental health and behaviour relies on questionnaires, interviews and rating scales rather than physical measurements, so how a condition was defined and measured shapes every result. Many studies are observational or small, placebo responses can be large, and findings in one group or culture may not carry over to another. Nothing on this page is advice about diagnosis or treatment; anyone worried about their mental health should talk to a qualified clinician. Check how outcomes were measured, who took part and how long they were followed.
Evidence from open-access studies
These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.
| Study / authors | Year | Source label / design | Europe PMC citations | Licence / source |
|---|---|---|---|---|
| Harm Reduction and Treatment Among People at High Risk of Overdose | 2024 | Research article Design not recorded in structured metadata | 21 | cc by PMID 39133486 · DOI · PMC11320172 |
| The "Gateway" hypothesis: evaluation of evidence and alternative explanations | 2024 | Review article Design not recorded in structured metadata | 15 | cc by PMID 38849956 · DOI · PMC11157890 |
| Navigating the nexus between British Columbia's public consumption and decriminalization policies of illegal drugs | 2024 | Research article Design not recorded in structured metadata | 15 | cc by PMID 38783308 · DOI · PMC11112927 |
| Breaking barriers: evaluating access models for harm reduction vending machines | 2026 | Research article Design not recorded in structured metadata | 2 | cc by PMID 41343981 · DOI · PMC13331765 |
Harm Reduction and Treatment Among People at High Risk of Overdose [1]
Abstract reading summary — source excerpts
- Opening excerpt
- ImportanceRates of overdose deaths involving synthetic opioids remain high, increasingly involve stimulants combined with opioids, and are increasing rapidly in racially and ethnically minoritized communities, yet little is known about access to harm reduction and treatment services in these groups.
- Closing excerpt
- Additional communication regarding their importance may help increase the use of the services amidst a rapidly changing drug supply.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (289 words)
ImportanceRates of overdose deaths involving synthetic opioids remain high, increasingly involve stimulants combined with opioids, and are increasing rapidly in racially and ethnically minoritized communities, yet little is known about access to harm reduction and treatment services in these groups.ObjectiveTo characterize access and barriers to harm reduction and treatment in a racially and ethnically diverse population of people who use drugs.Design, setting, and participantsA cross-sectional telephone survey of people recruited from 39 treatment, harm reduction, and social service organizations in Milwaukee County, Wisconsin; Flint and Detroit, Michigan; and statewide in New Jersey was conducted from January 30 to July 28, 2023. Adults who used cocaine, methamphetamine, or opioids in the past 30 days called a study hotline and completed an interview in English or Spanish.ExposuresOverdose experience, drug types used (opioids only, stimulants only, and polysubstance), and social risk factors (eg, financial instability and criminal legal involvement).Main outcomes and measuresRecent use of any harm reduction services, fentanyl test strips, naloxone possession, treatment, and self-reported barriers to services.ResultsOf the total sample of 1240 adults, 486 (39.2%) were Black non-Hispanic, 183 (14.8%) were Hispanic, and 464 (37.4%) were White non-Hispanic. In the past 30 days, 826 individuals (66.6%) were polysubstance users, 135 (10.9%) used only opioids, and 279 (22.5%) used only stimulants. A total of 349 respondents (28.1%) experienced a prior-year overdose. Compared with those without a prior-year overdose, people with overdose were more likely to possess naloxone (80.7% vs 68.2%; P Conclusions and relevanceIn this cross-sectional study of people who used drugs in the past 30 days, findings highlighted low use of harm reduction and treatment services among people who use stimulants. Additional communication regarding their importance may help increase the use of the services amidst a rapidly changing drug supply.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 39133486 · DOI · PMC11320172
The "Gateway" hypothesis: evaluation of evidence and alternative explanations [2]
Abstract reading summary — source excerpts
- Opening excerpt
- BackgroundElectronic nicotine delivery systems (ENDS) offer a substantial harm reduction opportunity for adults who smoke and are unlikely to quit.
- Closing excerpt
- Policies based on misinterpreting a causal gateway effect may be ineffective at best, and risk the negative unintended consequence of increased cigarette smoking.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (339 words)
BackgroundElectronic nicotine delivery systems (ENDS) offer a substantial harm reduction opportunity for adults who smoke and are unlikely to quit. However, a major concern about ENDS is their use by non-smoking youth, and particularly whether ENDS are acting as a "gateway" that leads youth to later start smoking cigarettes. However, evidence for the gateway hypothesis can be interpreted in alternative ways, e.g. that youth who have certain characteristics were already predisposed to use both ENDS and cigarettes ("common liability" explanation).AimsThis commentary provides an evaluation of the gateway hypothesis that is accessible by a lay audience. This paper first reviews and evaluates the evidence interpreted as supporting the gateway hypothesis. Important alternative explanations (i.e., common liability) are discussed, as are different types of evidence (i.e., population-level trends) that can help differentiate between these competing explanations.OverviewEvidence for the gateway hypothesis is based on the finding that youth who use ENDS are more likely to also smoke cigarettes. However, this evidence suffers from an important flaw: these studies fail to fully account for some youths' pre-existing tendency to use products containing nicotine, and inappropriately interpret the results as ENDS use causing some youth to smoke. Common liability studies suggest that ENDS use does not, in and of itself, directly cause youth to later smoke cigarettes, beyond their pre-existing tendency to use products containing nicotine. Population-level trends show that youth cigarette smoking declined faster after ENDS use became common, which contradicts the central prediction of the gateway hypothesis (i.e. that youth smoking would be more common following ENDS uptake, than otherwise be expected).ConclusionEvidence offered in support of the gateway hypothesis does not establish that ENDS use causes youth to also smoke cigarettes. Instead, this evidence is better interpreted as resulting from a common liability to use both ENDS and cigarettes. Population-level trends are inconsistent with the gateway hypothesis, and instead are consistent with (but do not prove) ENDS displacing cigarettes. Policies based on misinterpreting a causal gateway effect may be ineffective at best, and risk the negative unintended consequence of increased cigarette smoking.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 38849956 · DOI · PMC11157890
Navigating the nexus between British Columbia's public consumption and decriminalization policies of illegal drugs [3]
Abstract reading summary — source excerpts
- Opening excerpt
- In January 2023, the province of British Columbia (BC) decriminalized the possession of certain illegal drugs for personal use.
- Closing excerpt
- Decision-makers are urged to increase engagement with PWUD and relevant stakeholders in the design and implementation of policies pertaining to public consumption to ensure that they effectively address the evolving needs and realities of PWUD, and align with decriminalization goals.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (304 words)
In January 2023, the province of British Columbia (BC) decriminalized the possession of certain illegal drugs for personal use. The province's primary intent was to reduce the stigma associated with drug use, as well as barriers for people who use drugs (PWUD) to access treatment and supports. However, less than ten months into the decriminalization policy, due to growing concerns about public safety voiced by municipal governments and communities, the provincial government made amendments to the policy to ban the public consumption of illicit drugs in additional locations, and subsequently introduced additional legislation, Bill 34, aimed at regulating public consumption of drugs in public spaces. Some communities have also implemented local bylaws similarly regulating public drug use. Bill 34 and local bylaws may serve as tools to promote community health and safety and minimize direct and indirect harms associated with public drug use. However, such legislation may re-criminalize PWUD and reinforce negative perceptions surrounding drug use, especially if these policies are not paired with strategies to expand the availability and accessibility of critical harm reduction and housing services. Without ample access to these services, limitations on public drug use can potentially displace individuals to areas where they are more likely to use alone, further exposing them to substance use-related harms, and undermining the goals of decriminalization. The potential effects of these restrictions may also disproportionately impact marginalized populations. As of April 2024, Bill 34 remains on hold. Moving forward, it will be important to monitor this bill, as well as other public consumption bylaws and legislation, and their impact on BC's overall decriminalization initiative. Decision-makers are urged to increase engagement with PWUD and relevant stakeholders in the design and implementation of policies pertaining to public consumption to ensure that they effectively address the evolving needs and realities of PWUD, and align with decriminalization goals.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 38783308 · DOI · PMC11112927
Breaking barriers: evaluating access models for harm reduction vending machines [4]
Abstract reading summary — source excerpts
- Opening excerpt
- The opioid epidemic continues to claim lives at alarming rates, disproportionately affecting marginalized communities, with structural barriers preventing equitable access to lifesaving interventions such as naloxone.
- Closing excerpt
- Further research is needed to evaluate the long-term impacts of unrestricted HRVM access models on overdose prevention and other health outcomes.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (190 words)
The opioid epidemic continues to claim lives at alarming rates, disproportionately affecting marginalized communities, with structural barriers preventing equitable access to lifesaving interventions such as naloxone. Harm reduction vending machines (HRVMs) offer a promising solution to this issue, providing low-barrier access to naloxone and other harm reduction supplies. This study examines the impact of different HRVM access models on product utilization, specifically focusing on an outdoor HRVM, Project HOPE, located in Bakersfield, California. Initially, the machine required participant registration and imposed product limits; however, these restrictions were removed in August 2023 to improve access. An interrupted time series analysis of data from June to October 2023 reveal a significant increase in product utilization following the shift to unrestricted access, with increases in demand for naloxone kits, safer injection kits, wound care kits, and other basic needs supplies. The findings suggest that removing barriers to HRVM access, including registration requirements and product limits, can significantly improve the utilization of harm reduction supplies, potentially reducing opioid-related fatalities and promoting health equity. Further research is needed to evaluate the long-term impacts of unrestricted HRVM access models on overdose prevention and other health outcomes.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 41343981 · DOI · PMC13331765
Key reviews and meta-analyses
The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.
- Research article Effectiveness and cost-effectiveness of policies and programmes to reduce the harm caused by alcohol [5]
- Research article Understanding gambling related harm: a proposed definition, conceptual framework, and taxonomy of harms [6]
- Research article Are needle and syringe programmes associated with a reduction in HIV transmission among people who inject drugs: a systematic review and meta-analysis [7]
- Research article Prevention, early intervention, harm reduction, and treatment of substance use in young people [8]
- Research article An overview of forensic drug testing methods and their suitability for harm reduction point-of-care services [9]
- Research article Methamphetamine use in the United States: epidemiological update and implications for prevention, treatment, and harm reduction [10]
Full-text reviews on EvidenceLib
Open-access review articles about this topic, reproduced in full with authors, licence and references.
Contextual factors affecting the implementation of drug checking for harm reduction: a scoping literature review from a North American perspective
Chloe Grace Rose, Victoria Kulbokas, Emir Carkovic et al. · Harm Reduction Journal 2023 · CC BY 4.0
Harm reduction program and hepatitis C prevalence in people who inject drugs (PWID) in Iran: an updated systematic review and cumulative meta-analysis
Abdolhalim Rajabi, Heidar Sharafi, Seyed Moayed Alavian · Harm Reduction Journal 2021 · CC BY 4.0
References
- Bandara S, Byrne L, Berman V, Hurst A, King D, Gibbons JB, et al.. Harm Reduction and Treatment Among People at High Risk of Overdose. . 2024. PMID 39133486 · DOI · PMC11320172
- Selya A. The "Gateway" hypothesis: evaluation of evidence and alternative explanations. . 2024. PMID 38849956 · DOI · PMC11157890
- Ali F, Law J, Russell C, Crépault JF, Goulão JC, Lock K, et al.. Navigating the nexus between British Columbia's public consumption and decriminalization policies of illegal drugs. . 2024. PMID 38783308 · DOI · PMC11112927
- Herrera A, Conner B, Beshirs P, Bluthenthal R. Breaking barriers: evaluating access models for harm reduction vending machines. . 2026. PMID 41343981 · DOI · PMC13331765
- Anderson P, Chisholm D, Fuhr DC. Effectiveness and cost-effectiveness of policies and programmes to reduce the harm caused by alcohol. Lancet. 2009. PMID 19560605 · DOI
- Langham E, Thorne H, Browne M, Donaldson P, Rose J, Rockloff M. Understanding gambling related harm: a proposed definition, conceptual framework, and taxonomy of harms. BMC Public Health. 2016. PMID 26818137 · DOI · PMC4728872
- Aspinall EJ, Nambiar D, Goldberg DJ, Hickman M, Weir A, Van Velzen E, et al.. Are needle and syringe programmes associated with a reduction in HIV transmission among people who inject drugs: a systematic review and meta-analysis. Int J Epidemiol. 2014. PMID 24374889 · DOI
- Stockings E, Hall WD, Lynskey M, Morley KI, Reavley N, Strang J, et al.. Prevention, early intervention, harm reduction, and treatment of substance use in young people. Lancet Psychiatry. 2016. PMID 26905481 · DOI
- Harper L, Powell J, Pijl EM. An overview of forensic drug testing methods and their suitability for harm reduction point-of-care services. Harm Reduct J. 2017. PMID 28760153 · DOI · PMC5537996
- Jones CM, Houry D, Han B, Baldwin G, Vivolo-Kantor A, Compton WM. Methamphetamine use in the United States: epidemiological update and implications for prevention, treatment, and harm reduction. Ann N Y Acad Sci. 2022. PMID 34561865 · DOI · PMC9097961
About this article
- Sources
- NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
- Verification
- Every reference was resolved against PubMed on 2026-11-04; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-11-04.
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Evidence strength
EvidenceHelix's computed view of the study designs behind this topic: how common meta-analyses, randomized trials and reviews are, how recent the literature is, and a plain-language reading. It describes the design mix of the literature. It is not a quality appraisal of any study, and it is not medical advice.