Understanding how spatial interactions of built environment features shape substance-use risk among youth in a rapidly urbanizing Nigerian city

In the crowded, fast-changing streets of cities across the developing world, a quiet but urgent public health challenge is taking shape: the rising use of alcohol, drugs, and other substances by young people. For decades, scientists have understood that a teenager's decision to use these substances is rarely just a matter of personal weakness or bad choices. Instead, it is deeply rooted in the world they inhabit. This world includes the people they know—friends and family who might use drugs themselves—and the physical environment they walk through every day, where substances might be easy to find or hard to avoid. When these social pressures and physical opportunities align, the risk of use grows. Understanding how these two forces work together, especially in rapidly growing African cities where regulations can be fragmented and urban life is intense, is essential for designing solutions that actually work.

A team of researchers set out to map this complex landscape in Lagos, Nigeria, one of the largest and most dynamic cities in Africa. They focused on the Yaba area, a dense urban neighborhood filled with markets, schools, and transport hubs, to understand how the social circles of young people and the availability of drugs in their immediate surroundings combine to shape behavior. The study did not just ask young people what they used; it asked them to describe their social world and their neighborhood, then looked for patterns in how these factors interacted. By listening to the voices of the youth themselves and combining those stories with hard data, the researchers built a clearer picture of why some young people start using substances while others do not, and what the community believes can be done to stop it.

The researchers gathered information from 285 young people between the ages of 12 and 24. They conducted face-to-face interviews in private settings to ensure safety and honesty, asking about their substance use over the last month, their friends, their families, and how easy it was to find drugs in their neighborhood. They also asked an open-ended question: how could substance abuse be reduced in your community? The results revealed that nearly one in four participants had used a substance in the past month. Among those who had ever used substances, those who used multiple types were significantly more likely to be using them recently. But the most revealing findings came from looking at the relationship between social pressure and physical access.

The study found that having friends or family members who use substances was a strong predictor of recent use. However, this social influence did not act in a vacuum. The researchers discovered that the danger of having a social circle that uses drugs became much more potent when the young person also believed that substances were easy to get in their neighborhood. In other words, social pressure alone was a risk factor, but when that pressure met an environment where drugs were readily available, the likelihood of use jumped significantly. It was as if the social pull to try a substance became impossible to resist when the physical barrier to obtaining it was low. This interaction suggests that the environment does not just add to the risk; it amplifies the influence of the people around the young person.

When the researchers looked at the specific neighborhoods within Yaba, they saw these patterns playing out on the ground. In areas like Makoko, where the streets are narrow and the population is dense, the perceived ease of finding substances was very high, and the rate of recent use was the highest in the study. In contrast, in areas like Abule Oja, where the perceived availability was lower, the rates of recent use were also lower. While the differences between neighborhoods were not statistically overwhelming, the map provided a clear visual story: the risk of substance use was not spread evenly across the city but was concentrated in specific pockets where social networks and easy access overlapped. The data showed that for every step up in a young person's "social exposure score"—a measure of how many friends or family members used drugs—their risk increased, but that increase was nearly double when they also reported that drugs were easy to find nearby.

The study also turned to the young people themselves for answers. When asked how to reduce substance use in their communities, the most common response was not about education or counseling, but about stopping the supply. Nearly half of the participants called for stricter law enforcement against those selling drugs. This aligns perfectly with the data showing that perceived availability is a major driver of use. The community also pointed to the need for awareness campaigns, better parental supervision, and economic opportunities for youth. These suggestions form a cohesive strategy: if the environment makes drugs too easy to find, and if young people lack other paths forward, social pressure will inevitably lead to use. The researchers noted that a small but notable group of participants expressed a sense of fatalism, feeling that nothing could be done to change the situation, which highlights a barrier that any future intervention must address.

This research moves beyond the old idea that substance use is simply a personal failing. Instead, it paints a picture of a young person navigating a world where their social circle and their physical surroundings are working together to shape their choices. The findings suggest that effective prevention cannot rely on telling young people to say "no" in a vacuum. It requires a multi-layered approach that simultaneously tightens the availability of substances in the community and strengthens the protective factors in a young person's life, such as family support and economic opportunity. By addressing the environment where drugs are sold and the social networks that normalize their use, cities like Lagos can begin to disrupt the cycle that leads so many young people down a dangerous path. The study confirms that to protect the next generation, we must change the world they live in, not just the minds they have.