It's simplest to think about risk on an individual level. Consider this example:
Sandra is a 12-year-old girl with a family history of alcoholism and mental illness. Sandra’s mother is a functioning alcoholic and her father suffers from undiagnosed depression. Over the past 5 years, Sandra’s family has moved four times: she now lives in a low-income neighborhood with high crime and many abandoned buildings. At night, neighborhood youth use the corner park to drink and use drugs. Sandra is bussed across town to attend school but lives close to her grandparents, with whom she has a close relationship. She attends an after-school program at the local Girls, Inc. where she is the lead scorer on her basketball team.
But it’s important to realize that every community includes many Sandras: Adolescents who live in conditions and experience combinations of risk and protective factors that place them at risk for substance abuse and other related behavioral health problems. As prevention practitioners, we focus not only on individuals but on whole populations, looking for ways to address risk and protective factors that contribute to problems on the population level.