Program Goals/Target Population
The Preventive Treatment Program (also known as the Montreal Longitudinal Study and as the Montreal Prevention Experiment) was a prevention program aimed at disruptive kindergarten boys and their parents, with the goal of reducing short- and long-term antisocial behavior. This program targeted white, Canadian-born, 7- to 9-year-old boys, from low-socioeconomic-status families, who were assessed as having high levels of disruptive behavior in kindergarten. The program provided training for both parents and boys with the long-term goal of decreasing delinquency, substance use, and gang involvement. The program was administered to treatment-group boys and their parents when the boys were 7 years old and lasted until they turned 9.
There is research literature that shows disruptive behavioral patterns that develop during the early school years dramatically increases the risk for later antisocial behavior (Farrington 1991; White et al. 1990). The primary “cause” of antisocial behavior has often been debated, with some arguing that ineffective parenting may lead to antisocial disorders, whereas others suggest genetic and perinatal factors increase the risk of criminality (Tremblay et al. 1995). Interventions that were designed to disrupt the development of antisocial behavior were often single-concentration programs that were either directed at parental practices or children’s social skills, but not both. However, it was proposed that interventions that attempt to change the course of disruptive behavior should concentrate on changing the different sources of influence that affect the development of antisocial behavior (Coie and Jacobs 1993). Based on this prior research, the Preventive Treatment Program was developed as a multimodal approach to reduce antisocial behavior through parent-focused and child-focused components.
The program included a home-based parent training component and a school-based social skills training component. The parent-training component was based on a model developed at the Oregon Social Learning Center. Parents received an average of 17 sessions that concentrated on monitoring their children’s behavior, giving positive reinforcement for prosocial behavior, using punishment effectively, and managing family crises. Caseworkers helped parents generalize what they learned through home visits, and teachers were encouraged to cooperate with the intervention.
The school-based component emphasized promoting social competence and emotional regulation by stressing problem-solving skills, life skills, conflict resolution, and self-control. The training was provided in small groups, which included one or two disruptive boys with a group of three to five peers whom teachers identified as prosocial. Interactive learning methods and behavioral management techniques such as coaching, peer modeling, self-instruction, reinforcement contingency, and role-playing to build skills were used to promote positive change. Sessions during the first year concentrated on developing prosocial skills with themes such as “how to invite someone into a group” and “how to make contact.” The second year concentrated on promoting self-control skills with themes such as “what to do when I am angry” and “look and listen.”
The program was implemented by a multidisciplinary team consisting of two university trained child-care workers, one psychologist, and one social worker. Each case worker was responsible for providing the home-based parent training component to parents of 12 families and the school-based component to 12 boys from 12 other families. This created a team approach whereby two professionals could coordinate their efforts with one family (one with the parents at home, the other with the child at school).
Overall, Tremblay and colleagues (1995) found mixed results with regards to the effectiveness of the Preventive Treatment Program. There were some positive effects found in the short term, but the effects seemed to disappear by the time the boys were 15 years old (6 years after the end of the intervention). However, Boisjoli and colleagues (2007) found some positive effects by the time the boys were 24 years old (15 years after the end of the intervention), while Vitaro and colleagues (2013) found mixed effects through the time the boys were 28 years old (19 years after the end of the intervention).
Tremblay and colleagues (1995) found that although a larger proportion of boys in the treatment group were in an age-appropriate regular classroom during the elementary school years (ages 10 to 12) compared with boys in the control group, the group difference disappeared from age 13 onward (during the high school years). At age 15, approximately 40 percent of boys in both groups were in a regular third year of high school class as expected. A repeated log-linear analysis also detected no significant group differences.
In the overall sample of boys in the study, there was a significant decrease in teacher-rated disruptiveness over time. However, there were no significant differences between the treatment and control groups.
There were significant between-group differences on measures of self-reported delinquency, indicating that the treatment group was reporting significantly fewer delinquent behaviors 1 to 6 years after the end of the intervention. However, there were no significant differences between the treatment and control groups when the total self-reported delinquency score was broken down into the stealing, vandalism, and drug use subscales.
Juvenile Court Records
A total of 30 boys (3.3 percent of the total sample) were found to have been placed under the Juvenile Offenders’ Act from ages 12 to 15 (youths are placed under this act if they are arrested by the police, charged, and found guilty of having broken a Canadian law and are thus considered “delinquents”). Of the treatment group, 9.3 percent were placed under the Act, compared with 7.4 percent of the control group. This difference was not statistically significant.
Perceptions of Parenting
In the overall sample, the boys perceived that they were being punished less and less as they became older. However, there were no significant differences between the treatment and control groups. In addition, treatment group boys perceived more supervision from their parents than the control group boys did; however, the difference was not statistically significant.
High School Graduation
At age 24, Boisjoli and colleagues (2007) found that the treatment group had a significantly higher rate of high school graduation compared with the control group. In the treatment group, 45.6 percent had graduated from high school, compared with 32.2 percent of the control group.
The treatment group had a lower rate of criminal records compared with the control group (21.7 percent versus 32.6 percent), although the difference only approached statistical significance (p=0.06).
Vitaro and colleagues (2013) found that boys’ participation in the Preventive Treatment Program produced no significant differences on personal violence as compared with the control group at any of the three developmental periods (early adolescence, mid-adolescence, and late adolescence/early adulthood).
Boys who participated in the Preventive Treatment Program reported significantly lower property violence than boys in the control group across all three developmental periods.
Tremblay and colleagues (1995) employed a longitudinal, randomized design to test the efficacy of the Preventive Treatment Program. In 1984, as part of the Montreal Longitudinal Study, teachers in 53 Montreal, Quebec schools with the lowest socioeconomic status index assessed all kindergarten boys in their classes (n=1,161). The general aim of the study was to prospectively examine the development of a large sample of inner-city kindergarten boys, with a particular focus on antisocial behavior. From this sample, a subgroup of boys identified as disruptive in kindergarten was selected to test the effects of the Preventive Intervention Program.
Boys who were rated above the 70th percentile on the disruptive scale of the Social Behavior Questionnaire (n=366) were considered to be at risk for later antisocial behavior. Of these boys, 319 were randomly assigned to a treatment group (n=96), a control group (n=71), or an attention-placebo control group (n=152). Because of the refusal of some subjects to participate in the study, data was analyzed on 166 boys, including 43 in the treatment group, 41 in the control group, and 82 in the attention-placebo control group. However, because there were no between-group differences between the attention-placebo control group and the control group on any of the measures of interest, the two conditions were combined to form a single comparison group.
The treatment group received the preventive intervention that was administered to the boys and their parents when the boys were 7 years old and lasted until they turned 9. The attention-placebo control group boys participated in an intensive (school based, home based, and laboratory based) observational study. Every second year the families were visited during four evenings. Families also came to the university laboratory for a 3-hour session on a Saturday. The child was observed for a half-day at school on four occasions and spent a whole day in the university laboratory during the summer. The control group boys did not receive an intervention.
The three groups of disruptive boys were compared with a population-based random sample of kindergarten boys from French public schools in the Canadian province of Quebec in 1986–87 (n=1,000). Families participating in the study were significantly more likely to be socioeconomically disadvantaged than the representative sample of their same-sex peers. In addition, parents of the disruptive boys in the study were consistently younger at the birth of their sons, and the total family income was lower.
The total sample of boys was assessed annually from age 10 (1 year after the end of the intervention), with the most recent analyses occurring when the boys were 15 (6 years after the end of the intervention). The outcome measures of interest included school adjustment, disruptive behavior, delinquency, and parenting behavior. School adjustment was measured by examining whether boys were placed out of a regular classroom appropriate for their age. At age 10 the boys should have been in a regular fourth grade class, and by age 15 they should have been in their third year of high school. Disruptive behavior was measured using teachers’ ratings on the Social Behavior Questionnaire. From ages 10 to 12, boys had one main elementary school teacher for the day. From ages 13 to 15, most boys had more than one teacher every day, so math and French teachers were used as raters because they had the most contact with the boys. For self-reported delinquency, boys completed a questionnaire addressing their involvement in antisocial behavior from ages 10 to 15. Eleven questions asked about theft, three questions asked about alcohol and drug use, and six questions asked about vandalism. At age 10, the boys were asked to report if they had ever misbehaved in the specified ways. From age 11, they were asked whether they had engaged in such behaviors in the previous 12 months. In addition to the questionnaire, juvenile court records were used to identify boys who had been placed under the Juvenile Offenders’ Act from ages 12 to 15 (this Canadian law does not apply before age 12). Youths are placed under this act if they are arrested by the police, charged, and found guilty of having broken a Canadian law. As such, they are officially designated as “delinquents.” Finally, parenting was assessed on the basis of boys’ perceptions of their parents’ childrearing practices, with questions specifically probing parental supervision and punishment during the previous 12 months.
To understand the effects of the treatment intervention from a development perspective, a repeated-measures approach was used to analyze the data.
Boisjoli and colleagues (2007) conducted a 15-year follow-up of the sample of boys from the 1995 study by Tremblay and colleagues. The main objective of the study was to examine whether boys who participated in the Preventive Treatment Program had higher rates of high-school graduation and lower rates of crime involvement compared with boys in the control group by age 24.
Data on whether participants had obtained their high school diploma by age 24 (as of 2003) was collected from the Ministry of Education of Quebec for 98 percent of the original study sample. Data on whether participants had criminal records by age 24 (as of 2003) was collected from official records for all participants from the original study sample.
Two sets of logistic regression analyses were conducted using the follow-up data. To test the effectiveness of the program, all participants in the treatment sample were included in the intention-to-treat analytic strategy, whether they received the intervention or not.
Vitaro and colleagues (2013) conducted a 19-year follow-up of the sample of boys from the 1995 study by Tremblay and colleagues. The goal of this study was to assess the impact of the Preventive Treatment Program on self-reported violent behaviors through age 28 using an intent-to treat (ITT) analysis. The violent behaviors measured were violence against persons (i.e., personal violence) and violence against property (i.e., property violence, including theft and vandalism).
Personal and property violence were measured using a 24-item Self-Report Delinquency Questionnaire (SRDQ; LeBlanc and Tremblay 1988), which assessed involvement in personal and property violence over the last 12 months.
Outcomes were examined at multiple points over three developmental periods: early adolescence (11–13 years old), mid-adolescence (14–16 years old), and late adolescence/early adulthood (17, 23, and 28 years old).
There is no cost information available for this program.
The Preventive Treatment Program originally received a final program rating of No Effects based on a review of the study by Tremblay and colleagues (1995). A re-review of new research by Boisjoli and colleagues (2007) was conducted in December 2012. Based on the evidence from both studies, the program received a new final rating of Promising. Promising programs have some evidence indicating they achieve their intended outcomes. An additional re-review of new research by Vitaro and colleagues (2013) was conducted in October 2014 and supported the program’s final rating of Promising.
Evidence-Base (Studies Reviewed)
These sources were used in the development of the program profile:Study 1Tremblay, Richard Ernest, Linda Pagani–Kurtz, Louise C. Masse, Frank Vitaro, and Robert O. Pihl. 1995. “A Bimodal Preventive Intervention for Disruptive Kindergarten Boys: Its Impact Through Mid-Adolescence.” Journal of Consulting and Clinical Psychology 63(4):560–8.Study 2Boisjoli, Rachel, Frank Vitaro, Eric Lacourse, Edward D. Barker, and Richard Ernest Tremblay. 2007. “Impact and Clinical Significance of a Preventive Intervention for Disruptive Boys.” British Journal of Psychiatry 191:415–19.Study 3
Vitaro, Frank, Mara Brendgen, Charles-Édouard Giguère, and Richard E. Tremblay. 2013. “Early Prevention of Life-Course Personal and Property Violence: A 19-year Follow-up of the Montreal Longitudinal-Experimental Study (MLES).” Journal of Experimental Criminology
These sources were used in the development of the program profile:Coie, John D., and Marlene R. Jacobs. 1993. “The Role of Social Context in the Prevention of Conduct Disorder.” Development and Psychopathology 5:236–75.Farrington, David P. 1991. “Childhood Aggression and Adult Violence: Early Precursors and Life Outcomes.” In Debra J. Pepler and Kenneth H. Rubin (eds.), Development and Treatment of Childhood Aggression. Hillsdale, N.J.: Erlbaum.Tremblay, Richard Ernest, Louise C. Masse, Linda Pagani–Kurtz, and Frank Vitaro. 1996. “From Childhood Physical Aggression to Adolescent Maladjustment: The Montreal Prevention Experiment.” Ray Dev. Peters and Robert J. McMahon (eds.), Preventing Childhood Disorders, Substance Abuse, and Delinquency. Thousand Oaks, Calif.: SAGE Publications.Vitaro, Frank, Edward D. Barker, Mara Brendgen, and Richard Ernest Tremblay. 2012. “Pathways Explaining the Reduction of Adult Criminal Behaviour by a Randomized Preventive Intervention for Disruptive Kindergarten Children.” Journal of Child Psychology and Psychiatry 53(7):748–56.Vitaro, Frank, and Richard Ernest Tremblay. 1994. “Impact of a Prevention Program on Aggressive Children’s Friendships and Social Adjustment.” Journal of Abnormal Child Psychology 22(4):457–75.White, Jennifer L., Terrie E. Moffitt, Felton Earls, Lee N. Robins, and Phil A. Silva. 1990. “How Early Can We Tell? Predictors of Childhood Conduct Disorder and Adolescent Delinquency.” Criminology 28:507–33.