Early prevention of life-course personal and property violence: a 19-year follow-up of the Montreal Longitudinal-Experimental Study (MLES)

Objectives

This study assessed the impact of a multi-component prevention program on personal and property violence across three developmental periods (early adolescence, mid-adolescence and late adolescence/early adulthood).

Methods

The preventive intervention targeted disruptive kindergarten boys from low socioeconomic status families when they were 7 through 9 years of age. A randomized control trial was conducted to assess the impact of the preventive intervention relative to a control group.

Results

Two different approaches to data analysis were adopted: an intention-to-treat (ITT) approach and an instrumental variable (IV) approach. Results from the ITT analysis showed that the level of property violence for the intervention group was persistently lower across the three developmental periods compared to the control group. However, the intervention group did not differ from the control group on personal violence throughout adolescence and early adulthood. Results from the IV analysis generally confirmed these findings.

Conclusions

The discussion focuses on the differential effects of the prevention program on personal versus property violence.