This study reports the follow-up in 1993 of 209 adults, aged 27 to 29 years, who as children had been enrolled in a controlled trial of the prevention of children's behavior disorders. One hundred four control subjects and 105 study subjects, representing 90% of the original cohort, responded to a questionnaire detailing their present social situation and habits, educational achievements, and emotional well-being. The study subjects overall reported significantly fewer neurotic symptoms (p <0.001) than the control subjects; the study women also reported significantly fewer depressive symptoms (p <0.001). A greater proportion of the study subjects, compared with control subjects, had undertaken a university degree or diploma (p <0.013), whereas fewer of the men had attended a school of technology (p <0.049). The study women were less likely to be obese, as defined by a body mass index of 25 or more (p <0.030). The study men and women tended to smoke less than their control subjects, though significant differences were not attained. These results in the experimental group reflected the behavior patterns recorded at 6 years of age, after initial preschool interventional therapy. It appears that the initial benefit obtained from active counseling of mothers about their preschool children's behavior may be long lasting, favorably affecting the individuals' psychologic well-being, educational achievements, and social habits as adults. (J PEDIATR 1996;129:136-9)