A Brazilian study based on postmortem toxicological analyses found that 53% of violent death victims had alcohol or drugs in their systems shortly after death. The study examined 3,577 cases in Belém (North), Recife (Northeast), Vitória (Southeast), and Curitiba (South), representing the four regions of the country. "The goal was to produce standardized and comparable data on the role of psychoactive substances in deaths from external causes in Brazil," says Henrique Silva Bombana , a biomedical toxicologist, postdoctoral researcher at the University of São Paulo's School of Pharmaceutical Sciences (FCF-USP), and the first author of the study.
The study was published in the journal Toxics.
Bombana explains that the study was made possible by a 2020 agreement between USP and the National Secretariat for Drug Policy and Asset Management ( SENAD ) to map the relationship between alcohol and drug use and violent deaths. The four state capitals were chosen based on two criteria: the magnitude of the problem and strategic relevance. "These cities were selected based on the mortality rate from external causes and because they're strategic points along the drug trafficking route," the researcher explains. The selection also considered the country's role as an international transit corridor. "Often, drugs come from other countries and pass through Brazil to be distributed to the United States, Europe, and Africa."
Data collection took place between 2022 and mid-2024. "We assembled and trained teams of four researchers in each city to collect blood samples during autopsies. This material was frozen and sent to our laboratory at USP, where a team of five researchers performed the analyses," Bombana explains.
The profile of the victims reflects the most common face of violent mortality in the country: 89.7% were male, 56% were 30 years of age or older, and 67.3% died from homicide. This last figure is especially relevant when compared to the percentages of deaths from traffic accidents (14.7%) and suicides (9.2%). In the North and Northeast regions, the highest percentage was of individuals classified as "brown," according to the nomenclature adopted by the Brazilian Institute of Geography and Statistics (IBGE), while in the Southeast and South regions, the majority were "white."
Of all the victims, 53% tested positive for at least one psychoactive substance. The most commonly detected substances were cocaine (29.6%), alcohol (27.7%), benzodiazepines (6.8%), and cannabis (2.2%). "The prevalence of cocaine was very significant in homicide cases, while alcohol was the most detected substance in traffic accident deaths. Benzodiazepines were prevalent in suicides," reports Bombana.
The laboratory analyses included alcohol and a range of illicit drugs and psychoactive medications using standardized protocols. The team also implemented operational precautions to minimize losses due to degradation. "Especially in the case of alcohol, if the sample isn't stored properly, the substance can degrade and skew the results," the researcher notes.
"The association between the substance and violent death in the case of homicide is very complicated, because we're only looking at the victim, not the perpetrator. Still, it's possible to attribute the high presence of cocaine not only to acute use of the substance but also to the social and economic context in which the illegal market operates – the environment of trafficking, selling, and buying that characterizes what we call structural violence," Bombana argues.
The presence of alcohol in traffic fatalities is a longstanding problem in the country. "The issue has been discussed for at least 30 years without a solution being found. The legislation is quite robust, but what may be lacking is greater control over the sale of alcohol. Some countries have much stricter and more restrictive rules for sales," the researcher notes.
The cross-sectional research does not allow for the establishment of cause-and-effect relationships. This type of study collects data at a single point in time, providing a snapshot of reality.
In the study, the researchers recorded the type of death (homicide, traffic accident, suicide, etc.) and the results of the postmortem toxicological analysis (cocaine, alcohol, benzodiazepines, etc.) for each victim. The researchers then compared the two sets of data. This makes it possible to measure prevalence – for example, "53% had some substance in their blood" – and to identify associations – for example, cocaine was more common in homicides, and alcohol was more common in traffic deaths. However, the study does not allow us to prove that cocaine "caused" the homicide through cause and effect. Similarly, the cross-sectional design alone does not "close" the causal chain between alcohol consumption and traffic fatalities. "What can be stated with certainty is the existence of consistent risk signals," notes Bombana.
When analyzing police records associated with homicide cases, the team found that approximately 85% of deaths were caused by gunshot wounds. "This occurred at a time when, through decrees and ordinances, the federal government at the time relaxed rules for purchasing and carrying firearms, increased limits on weapons and ammunition, expanded authorized categories, and reduced control and enforcement mechanisms – a context that helps explain the observed pattern of lethality," Bombana emphasizes.
The prominence of benzodiazepines in suicides raises questions about medication use, self-medication, and vulnerability. The researcher suggests a plausible hypothesis without attributing direct causality: "The use of these substances may end up serving as a trigger to transition from suicidal ideation to actual action."
More broadly, this observation summarizes a mechanism common to different forms of violent death: substance use can lead individuals to place themselves in more dangerous environments (in the case of homicides) or act more recklessly (in the case of traffic accidents).
The pattern of fatal incidents is not uniform. There are differences in patterns among the four state capitals studied: Recife has a high prevalence of alcohol-related deaths (either alone or in combination with other substances); Vitória and Belém have a higher concentration of deaths associated with illegal drug use (without alcohol); and Curitiba has a higher prevalence of alcohol-related deaths than illegal drug-related deaths. "Brazil is a vast country, and each city has its own social, cultural, health, and safety characteristics. Substance use patterns reflect these specificities," comments Bombana. According to the researcher, this heterogeneity should inform tailored interventions and public policies focused on the reality of each city or region.
Although he emphasizes that he is not a public policy specialist, Bombana argues that addressing the problem is more effective when centered on public health and harm reduction rather than repression. "Perhaps the criminalization policy, the so-called 'war on drugs,' isn't the best option. Portugal decriminalized drug use and saw a decrease in the number of users, petty crimes, homicides, and overdoses. The differences between Portugal and Brazil are enormous, of course. Starting with the size of the territories and populations. Still, the Portuguese example suggests that a harm reduction policy may be the most promising path."
The study was conducted by the "Alcohol, Drugs, and Violence" group at the USP Medical School (FM) and was coordinated by Bombana and Professor Vilma Leyton , who is also an author of the article. The study received support from FAPESP through a postdoctoral fellowship awarded to Bombana.
About São Paulo Research Foundation (FAPESP)
The São Paulo Research Foundation (FAPESP) is a public institution with the mission of supporting scientific research in all fields of knowledge by awarding scholarships, fellowships and grants to investigators linked with higher education and research institutions in the State of São Paulo, Brazil. FAPESP is aware that the very best research can only be done by working with the best researchers internationally. Therefore, it has established partnerships with funding agencies, higher education, private companies, and research organizations in other countries known for the quality of their research and has been encouraging scientists funded by its grants to further develop their international collaboration. You can learn more about FAPESP at www.fapesp.br/en and visit FAPESP news agency at www.agencia.fapesp.br/en to keep updated with the latest scientific breakthroughs FAPESP helps achieve through its many programs, awards and research centers. You may also subscribe to FAPESP news agency at http://agencia.fapesp.br/subscribe.
