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Preventive Treatment Program

Ages 7-9

Rating: Level 1


The Preventive Treatment Program (also known as the Montreal Longitudinal Study and the Montreal Prevention Experiment) was 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 males ages 7 to 9, from low socioeconomic 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 the treatment boys and their parents when the boys were 7 years old and lasted until they were 9.

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 who were teacher 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 1st year concentrated on developing prosocial skills with themes such as “how to invite someone into a group” and “how to make contact.” The 2nd year concentrated on promoting self-control skills with themes such as “what to do when I am angry” and “look and listen.”


A longitudinal, pretest, posttest, annual follow-up design was used to test the efficacy of the program. The total sample of boys assessed in kindergarten 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. Teachers in 53 Montreal, Quebec, schools with the lowest socioeconomic status index assessed all kindergarten boys in their classes (n=1,161). Boys who were rated above the 70th percentile on the disruptive scale of the Social Behavior Questionnaire (n=166) were randomly assigned to a treatment group (n=43), a control group (n=41), or an attention-placebo control group (n=82). Normative data was provided from a sample (n=1,000) drawn from the same population as the treatment subjects. Intervention was administered to the treatment boys and their parents when the boys were 7 years old and lasted until they were 9. The self-report questionnaire obtained annually concentrated on questions regarding juvenile delinquency, gang membership, age of onset of sexual intercourse, and academic motivation. Other sources of data included teachers, parents, peers, and official archival records.


Evaluations have demonstrated both short- and long-term gains for youths receiving the intervention.

At age 12, 3 years after the intervention,

  • Treated boys were less likely to report the following offenses: trespassing, taking objects worth less than $10, taking objects worth more than $10, and stealing bicycles.
  • Treated boys were rated by teachers as fighting less often than untreated boys.
  • 29 percent of the treated boys were rated as well-adjusted in school, compared with 19 percent of the untreated boys.
  • 22 percent of the treated boys, compared with 44 percent of the untreated boys, displayed less serious difficulties in school.
  • 23 percent of the treated boys, compared with 43 percent of the untreated boys, were held back in school or placed in special education classes.

At age 15, those receiving the intervention were less likely than untreated boys to report

  • Gang involvement
  • Having been drunk or taken drugs in the past 12 months
  • Having committed delinquent acts (stealing, vandalism, drug use)
  • Having friends arrested by the police

Risk Factors


  • Anti-social behavior and alienation/Delinquent beliefs/General delinquency involvement/Drug dealing
  • Early onset of aggression and/or violence


  • Family management problems/Poor parental supervision and/or monitoring
  • Parental use of physical punishment/Harsh and/or erratic discipline practices


  • Economic deprivation/Poverty/Residence in a disadvantaged neighborhood


  • Association with delinquent and/or aggressive peers
  • Peer rejection

Protective Factors


  • Healthy / Conventional beliefs and clear standards
  • Social competencies and problem-solving skills


  • Effective parenting
  • Rewards for prosocial family involvement


  • Good relationships with peers
  • Involvement with positive peer group activities


  • OJJDP: Blueprints
  • HHS: Surgeon General


Tremblay, Richard E., Louise Masse, Linda Pagani, and Frank Vitaro. 1996. “From Childhood Physical Aggression to Adolescent Maladjustment: The Montreal Prevention Experiment.” In R.D. Peters and R.J. McMahon (eds.). Preventing Childhood Disorders, Substance Abuse, and Delinquency. Thousand Oaks, Calif.: Sage Publications.

Tremblay, Richard E., Frank Vitaro, Llucie Bertrand, Marc LeBlanc, Helene Beauchesne, Helene Bioleau, and Lucille David. 1992. “Parent and Child Training to Prevent Early Onset of Delinquency: The Montreal Longitudinal Experimental Study.” In Joan McCord and Richard Tremblay (eds.). Preventing Antisocial Behavior: Interventions From Birth Through Adolescence. New York, N.Y.: The Guilford Press.

Tremblay, Richard E., Joan McCord, Helene Bioleau, Pierre Charlebois, Claude Gagnon, Marc LeBlanc, and Serge Larivée. 1991. “Can Disruptive Boys Be Helped to Become Competent?” Psychiatry 54:149–61.


Richard E. Tremblay, Ph.D.
University of Montreal, GRIP
3050 Edouard Monpetit
Montreal, Quebec H3T 1J7
Phone: (514) 343-6963
Fax: (514) 343-6962
Web site: