Abstract
Background Maladaptive family environments harm child development and are passed across generations. Childhood interventions may break this intergenerational cycle by improving the family environments children form as adults. The present study investigates this hypothesis by examining follow-up data collected 18 years after the end of the childhood Fast Track intervention designed to prevent externalizing problems. Methods We examined whether Fast Track assignment from grades 1 to 10 prevented the emergence of maladaptive family environments at age 34. A total of 400 (n = 206 in intervention condition, n = 194 controls) Fast Track participants who were parents at age 34 were surveyed about 11 aspects of their current family environment. The hypotheses and analytic plan were preregistered at and the Fast Track trial was registered at (NCT01653535). Results Multiple group linear regression models revealed that mothers who participated in the Fast Track intervention as children had lower depression symptoms, alcohol problems, drug problems, corporal punishment use, and food insecurity compared to control group mothers. All effects were modest in magnitude. However, for these same mothers, the Fast Track intervention had no effect on cannabis problems, experiences of romantic partner violence, or maternal use of physical aggression or warmth with their children. Additionally, mothers in the Fast Track intervention group reported higher levels of family chaos than those in the control group, but this effect may be a byproduct of the higher number of children per household in the intervention group. No intervention effects were found for fathers who participated in the Fast Track intervention as children. Conclusions Childhood assignment to Fast Track has some beneficial effects for girls, but not boys, on the family environments these individuals formed as adults 18 years later.