Promoting positive adult functioning through social development intervention in childhood: long-term effects from the Seattle Social Development Project.

OBJECTIVE To examine the long-term effects of the Seattle Social Development Project intervention in promoting positive adult functioning and preventing mental health problems, crime, and substance use (including tobacco, alcohol, and other drugs) at 21 years of age. DESIGN This nonrandomized controlled trial followed up participants to 21 years of age, 9 years after the intervention ended. We compared the following 3 intervention conditions: a full 6-year intervention (grades 1 through 6); a late 2-year intervention (grades 5 and 6 only); and a no-treatment control condition. SETTING Eighteen public elementary schools serving diverse neighborhoods, including high-crime neighborhoods, of Seattle, Wash. PARTICIPANTS A sex-balanced, multiethnic sample of 605 participants across the 3 conditions who completed interviews at 21 years of age (94% of the original sample in these conditions). INTERVENTIONS Teacher training in classroom instruction and management, child social and emotional skill development, and parent training. MAIN OUTCOME MEASURES Self-reports of functioning in school and work, emotional and mental health, and crime and substance use at 21 years of age and official court records. RESULTS Broad significant effects on functioning in school and work and on emotional and mental health were found. Fewer significant effects on crime and substance use were found at 21 years of age. Most outcomes had a consistent dose effect, with the strongest effects in subjects in the full-intervention group and effects in the late-intervention group between those in the full-intervention and control groups. CONCLUSIONS A theory-guided preventive intervention that strengthened teaching and parenting practices and taught children interpersonal skills during the elementary grades had wide-ranging beneficial effects on functioning in early adulthood.