Parents’ alcohol and drug use influences their children’s consumption, research shows

(Press-News.org) “Like father, like son? Can parenting styles break the intergenerational pattern of alcohol and drug use?” A group of Brazilian researchers analyzed data on the behavior of 4,280 adolescents and their guardians based on this question, arriving at two important conclusions.

Yes, parental attitudes are one of the most relevant factors in preventing alcohol and drug use among young people. However, the way guardians educate their children can significantly mitigate the risk, even in families where caregivers use these substances, including cigarettes, vapes (which are banned in Brazil), and marijuana.

The reduction in risk is more significant when the relationship between generations is marked by bonding, presence, dialogue, and clear rules of conduct – characteristics of the so-called “authoritative” parenting style, which combines acceptance and monitoring. Four parenting styles were analyzed in total (see table). The other styles were authoritarian, which reduced the risk of drug use but had less impact on alcohol, as well as permissive and neglectful. The latter two did not have any protective effects.

Consumption profiles were divided into three groups: abstainers, those who only drink alcohol, and those who use two or more substances.

Alcohol consumption by parents was associated with a 24% probability of their children using alcoholic beverages and a 6% probability of their children using two or more drugs. If guardians consume multiple substances, the risk of young people using them rises to 17% and 28%, respectively.

These findings were published on the Addictive Behaviors website and are described in an article in the March issue of the scientific journal.

“With this study, we reinforce the fact that parents’ patterns of alcohol and other drug use influence their children’s. However, if they set rules and limits at home and show affection, these protective factors greatly minimize the risk they themselves pose when they consume these substances. In addition, the greatest predictor of abstinence among young people is non-use by their guardians. When they’re abstinent, 89% of adolescents also don’t use alcohol or other legal or illegal drugs. This was the strongest association we found,” says Zila Sanchez, a professor in the Department of Preventive Medicine at the São Paulo School of Medicine of the Federal University of São Paulo (UNIFESP) and the lead author of the article.

Sanchez is the coordinator of the Research Center for the Prevention of Alcohol and Other Drug Use (PREVINA) at UNIFESP and has published dozens of studies on the subject, including one in 2017, which demonstrated a gradual association between parenting styles and drug use by adolescents.

At the time, the results showed that young people with negligent parents were more likely to attend class under the influence of drugs.

A broader view

The research is part of the project “Reducing Alcohol Consumption Among Adolescents Through a Community-Based Multicomponent Intervention,” which is funded by FAPESP. FAPESP also supported the article through a postdoctoral fellowship for Luis Eduardo Soares dos Santos.

The project was developed in four small municipalities in the state of São Paulo: Cordeirópolis, Iracemápolis, Salesópolis, and Biritiba-Mirim. It seeks to investigate effective community strategies for preventing alcohol use among adolescents and produce scientific evidence to guide public policies and prevention programs. With populations ranging from 18,000 to 25,000 residents and geographical diversity, the towns provide different contexts for these young people.

“The article is based on data from what we call a needs assessment, that is, when we diagnose the situation related to adolescents in the municipality. This is the pre-intervention phase to understand what these young people and their parents are like. We use extremely consolidated instruments to measure styles, but we innovate by working with the data alongside the consumption profiles of parents and children, looking at patterns,” the professor explains to Agência FAPESP.

The data were collected from 2023 to 2024 in four towns. The average age of the adolescents was 14.7 years, with nearly equal numbers of boys and girls. The most frequent behaviors among the children were alcohol consumption in the last month (19.9%) and episodic excessive consumption (11.4%). Among parents, the percentages were 56.4% and 20.3%, respectively. There was no separate analysis for whether the guardian was the father or the mother.

The researchers applied Latent Class Analysis (LCA) to identify substance use profiles in both generations and modeled their association using Latent Transition Analysis (LTA).

LCA is a statistical technique that identifies unobservable subgroups (latent classes) within a population based on response patterns in observed variables. It probabilistically estimates each individual belonging to these classes.

LTA is also a statistical technique that identifies “hidden” groups (latent classes) and estimates the probabilities of transition between them. In longitudinal studies, these transitions represent changes over time. In this study, “transition” refers to the association between generations; that is, the probability that adolescents will belong to certain substance use profiles depending on the profile observed in their parents.

The professor points out that, during the diagnostic phase, the group worked with all adolescents enrolled in schools in the four municipalities.
 
Impacts

Sanchez points out that, even in families with good parenting practices, adolescent alcohol use is associated with parental alcohol consumption, which reinforces the need for caution when normalizing this behavior at home. “When consumption is frequent and treated as something trivial, it translates into greater risk, regardless of the existing emotional bond,” she adds.

Alcohol is one of the main risk factors for the increase in chronic noncommunicable diseases around the world, including cardiovascular disease, cancer, and diabetes. In addition to physical effects, such as liver damage, cardiovascular system impairment, and increased vulnerability to infections, alcohol increases the likelihood of anxiety, difficulty concentrating, and depressive disorders.

Delaying the onset of substance use among young people is considered one of the most effective strategies for reducing future consumption and subsequent harm. Epidemiological studies have shown that community-based interventions consisting of school prevention programs for adolescents, family programs, and environmental strategies for the community promote more consistent and long-term effects.

In Brazil, despite the prohibition of alcohol sales to minors under 18, more than half of the population (56%) tried alcohol before that age, and 25.5% began regular drinking at that stage, according to the National Survey on Alcohol and Drugs (LENAD III), conducted by UNIFESP in partnership with the Ministry of Justice and Ipsos Public Affairs, and released in 2025.

The survey shows that just over a quarter (27.6%) of adolescents aged 14 to 17 have consumed alcohol at some point in their lives, corresponding to approximately 3.2 million individuals. In the last year, 19% reported use – the equivalent of 2.2 million young people.

Regarding marijuana, LENAD shows that approximately 1 million adolescents have used it at some point in their lives, with half of them using it in the last year. Among the general population, nearly one in five Brazilians (18.7%) has tried at least one psychoactive substance (excluding alcohol and tobacco products).

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.

 

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