Young adults are at risk of emotional and mental health problems, involvement in crime, and substance abuse. Studies have shown that early childhood interventions can have a positive impact on adolescents and young adults. Interventions for children six to 11 years of age are most appealing because elementary school programs can reach large groups of children. Studies have shown that interventions in this age group have a positive effect over time, but none have specifically evaluated the effects into early adulthood. Hawkins and associates assessed the long-term effects of childhood interventions, focusing on positive adult functioning and prevention of mental health problems, criminal involvement, and substance abuse at 21 years of age.

The nonrandomized controlled study evaluated participants in the Seattle Social Development Project, which included students from 18 public elementary schools, including eight in high-crime areas. The schools were randomly assigned to three intervention groups (i.e., full intervention, first to sixth grade; late intervention, fifth and sixth grade; and no intervention, control group). Intervention included teacher training, parent training, and social and emotional skill development for the child. The main outcome measures were self-reported school and work functioning, emotional and mental health, criminal involvement, and substance abuse. Additional information was obtained from court records.

The follow-up sample included 605 participants who were interviewed at 21 years of age. The full-intervention group functioned significantly better at school or at work in seven of the eight outcomes compared with the control group. The late-intervention group had some positive social function outcomes, but none were statistically significant when compared with the control group. The full-intervention group reported fewer problems in all of the emotional and mental health outcomes compared with the late intervention group, except in meeting diagnostic criteria for depression. The late-intervention group had better emotional and mental health responses than the control group, but few differences were statistically significant. The intervention groups had fewer significant criminal and substance abuse outcomes. There was a dose effect when comparing the groups, with the full-intervention group having the strongest effect, the late-intervention group next, and the control group last.

The authors conclude that an intervention focused on strengthening teaching and parenting practices and teaching elementary-age children interpersonal skills had a positive impact on these individuals into early adulthood.