Exploring the association between urban sprawl and mental health

•Urban sprawl levels have not been shown to be a significant risk factor for mental illness, since the population living in more sprawling areas presents a lower risk of developing psychological distress.•The more likely factor in influencing the probability of mental illness might not be so much the built environment, in this case the urban sprawl, but rather the socioeconomic conditions of the population residing in one zone or another.•Urban planners should consider new opportunities aimed at the improvement of population's mental health, putting the research into action through policies, plans, design, and development actions.