People with drug use disorders involving stimulants, opioids, sedatives or cannabis were 4 to 10 times more likely to perpetrate violence than comparison groups in a systematic review cited by a new United Nations Office on Drugs and Crime report.

The UN agency stresses that this relationship is probabilistic, not inevitable. Most people who use drugs do not become violent, while risks vary with the substance, pattern of use, mental health, trauma, poverty and surrounding environment.

A separate systematic review cited in the report found drugs in more than one-third of hospital presentations involving violence-related or assault injuries.

Among patients with firearm injuries, reported drug-detection rates ranged from 7% to 49%. Detecting a substance does not, however, establish that it caused the injury or violence.

Drug links appeared in 56% of England and Wales homicides

Official homicide data show that 56% of homicides in England and Wales during the year ending March 2024 involved a known drug user or dealer, or were related to drugs in another way.

That is a broad measure of involvement rather than proof that drug use caused each homicide.

The UN report classified 18% of homicides as involving systemic drug-market factors, 13% as involving psychopharmacological factors and 7% as involving an economic need to obtain drugs.

Those categories were not necessarily mutually exclusive. Only 29% of homicides met the criteria for at least one of the three more narrowly defined pathways.

The report describes the psychopharmacological pathway as harm associated with intoxication or withdrawal, including impaired judgment, agitation and reduced impulse control.

The economic-compulsive pathway covers offences committed to finance dependent drug use. The systemic pathway includes disorder, intimidation and violence arising around local drug markets and public drug-use settings.

Arrest data show large differences by substance

In an Australian sample of arrestees from 2021, 50% of respondents who had used methamphetamine said its use or acquisition contributed to their arrest.

The comparable share was 45% among heroin users and 14% among cannabis users. Almost 30% of arrestees attributed their offence to alcohol use.

These figures were self-reported by people who had already entered the criminal justice system. They should not be interpreted as estimates for everyone who uses those substances.

The report also cites 2018 data from Nigeria showing that nearly 1 in 8 people who had never used drugs experienced consequences from another person’s drug use.

Reported consequences included feeling threatened, being physically harmed and having money or valuables taken to pay for drugs.

Poverty and trauma can increase the risks

UNODC identifies poverty, unemployment, homelessness, limited access to healthcare, mental health conditions and exposure to violence as factors that can worsen safety outcomes.

The availability of weapons, weak social support and neighbourhoods with established drug markets can further increase the risk.

Women who use drugs were more likely to experience violence in intimate or exploitative settings, according to the report. Men were more likely to be involved in drug-related violence and acquisitive offences.

Young people were also identified as particularly vulnerable because substance use, impulsivity and exposure to violent environments can overlap with limited educational and employment opportunities.

These findings add a drug-use dimension to earlier StatsJournalist coverage of global safety perceptions, which examined the importance of policing, community services and local conditions.

Evidence spans 86 interviews in six cities

The thematic chapter combines scientific literature, national crime reports, prisoner and arrestee surveys, and qualitative evidence from 86 interviews.

The interviews involved people with lived experience, service providers and law-enforcement personnel in six cities: Bangkok, Cape Town, Dakar, Delhi, Nairobi and São Paulo.

They were conducted between October and mid-December 2025. UNODC cautions that the interviewees’ experiences may not represent their entire city or country.

Interviewees repeatedly described drug-related harms spreading beyond the individual to families, neighbourhoods, healthcare providers and criminal justice systems.

Reported effects included household financial losses, neglect of family responsibilities, theft, victimization, impaired driving, public disorder and fear within communities.

Why it matters

The report’s central message is not that drug use automatically produces violence. It argues that the likelihood and form of harm depend heavily on personal circumstances, social conditions and public policy.

UNODC cites research suggesting that treatment, housing support and accessible health and social services can reduce violence and offending among some people with drug use disorders.

The report also warns against directly comparing percentages from different countries. Its sources cover different years, populations, definitions and data-collection methods.

Arrestee surveys, treatment samples and interviews can identify recurring patterns, but they cannot provide a single global estimate of how much crime is caused by drug use.

The evidence instead points to a conditional relationship: drug use can heighten safety risks, but poverty, trauma, mental health, stigma, weapon availability and access to services help determine how severe those risks become.