Prevention science

Components of prevention scienceMrazek, P. B., Haggerty, R. J., Institute of Medicine (U.S.)., & United States. (1994). Reducing risks for mental disorders: Frontiers for preventive intervention research. Washington, D.C: National Academy Press.

Usefulness of risk factors

1. To identify subpopulations more likely to develop problems which should be reached by preventive intervention.
2. To identify malleable individual or environmental characteristics that can be changed by preventive intervention.

   Further observations about risk and protective factors

• Different forms of dysfunction are typically related to many different risk factors, rather than a single risk factor. On the other hand, a single risk factor may lead to a variety of consequences in different settings.
• Risk factors have compounding effects on an individual. The risk of dysfunction seems to increase exponentially with each additional exposure to a new risk factor.
• Some risk factors may predict dysfunction only at specific periods of development, while others stay constant throughout one's lifespan. As a general rule, prediction is best made from proximal risk factors.
• Diverse disorders may share common fundamental risk factors. For example, marital discord has been found to precede both conduct problems in children and depression among women.

  Levels of prevention

Guidelines for prevention

Foundation guidelines

• Start prevention early before a problem arises.
• Prevention interventions should include and reach those at high risk for the problem.
• Address malleable risk factors for the problem to be prevented.
• Strengthen malleable protective factors against the problem.
• Base prevention program in a clear and believable theory of change.
• Ensure adequate financing for full implementation by utilizing cost-benefit analyses.

  Intervention guidelines

• Specify clear goals with specific and measurable objectives.
• Build a community of support for the intervention.
• Choose interveners who are trusted, respected people whom recipients will listen to and develop a relationship with.
• Provide a standard protocol or manual for intervention activities that is easily available.
• Allow flexible implementation of protocol to meet needs of the program.
• Provide proper and adequate training for the interveners on the program protocols.
• Provide referrals to other services if needed by participants.
• Make services available and accessible to clients in their local community.
• Ensure intervention is culturally competent for the target population.
• Specify the duration of the intervention and provide sufficient amount to achieve a positive behavior change.
• Document all activities occurring during the program in order to monitor fidelity.

  Convincing evidence guidelines

• The preventive intervention has been tested in a randomized controlled trial; or with an interrupted time series design with enough data points before and after intervention to allow threats to internal validity of results to be ruled out; or with a quasi-experimental design with a comparison group in which the researchers have ruled out plausible threats to internal validity.
• The population in which the preventive intervention was tested was properly described.
• The trial found outcomes that were statistically significant improvements for the intervention group compared to the control group.
• The trial experienced little or no differential attrition from intervention versus control condition.
• Longitudinal follow up of participants and controls found sustained effects.
• The intervention was found to be most effective with those at highest risk of the problem.
• Results have been replicated in two or more trials.
• Trial may or may not be conducted by an independent evaluator.

  Effects on adolescent health

• The Nurse Family Partnership program, which provides regular home visits with nurses to poor, first-time mothers. The program led to 43 percent fewer subsequent pregnancies and decreased the mothers' welfare use, smoking and arrests. As the children grew up, they drank less alcohol, were less likely to be arrested and had fewer sex partners than children whose mothers were not in the program.
• The Gatehouse Project, including a curriculum focused on building social, problem-solving and coping skills in schoolchildren and more positive classroom and school-wide environments, led to decreased smoking and other substance use and delayed the onset of sexual intercourse in adolescents.
• In low-income countries, the Conditional cash transfer programs, paid school fees and gave about $10 a month to mothers to ensure their children attend school. As a result, more girls stayed in school and adolescent pregnancies declined.

  Case study: nurse family partnership

Evidence of effectiveness

Study 1: Elmira, NY

Effects on child

• 48% fewer officially verified incidents of child abuse and neglect as of age 15.
• 43% less likely to have been arrested, and 58% less likely to have been convicted, as of age 19.
• 57% fewer lifetime arrests and 66% fewer lifetime convictions, as of age 19.
• No significant effect on recent substance use.
• No significant effect on high school graduation rates.
• No significant effect on likelihood of becoming pregnant or giving birth, or causing a pregnancy or birth.
• No significant effect on percent engaged in economically productive activities at age 19, or on lifetime use of welfare or other public assistance, per self-reports.

  Effects on mother

• 20% less time spent on welfare. This effect was statistically significant at the.10 level, but not the.05 level.
• 19% fewer subsequent births.
• 61% fewer self-reported arrests.
• 72% fewer self-reported convictions.
• There were no significant effects on months employed, months on food stamps or Medicaid, or behavior-impairing substance abuse.

  Study quality

Study 2: Memphis, TN

Effects on child at age 2

• 23% fewer health care encounters for injuries or ingestions.
• 78% fewer days hospitalized for injuries or ingestions.

  Effects on child at age 12

• 67% less likely to have smoked cigarettes, consumed alcohol, or used marijuana in the past month.
• 28% less likely to have an internalizing disorder, such as depression or anxiety.

• Scored 6 percentile points higher on the Tennessee state reading and math achievement tests in grades 1-6.
• Had 8% higher reading and math GPA in grades 1-6.

  Effects on mother when child reached age 12

• 9% reduction in time on welfare during the 12 years of having their first child.
• 9% reduction in time on food stamps during the 12 years of having their first child.
• 10% reduction in annual government spending per person on welfare, food stamps, and Medicaid during the 12 years of having their first child.
• 16% reduction in subsequent births during the first 6 years of their first child's life.

  Study quality

Study 3: Denver, CO

Effects on child at age 4

Effects on mother when child reached age 4

• 20% longer interval between the women's 1st and 2nd births.
• Lower percentage of women experienced domestic violence from their partner in the past 6 months.

  Discussion of study quality

• This was a large study with a moderately long-term follow-up of age 4 for the first-born child.
• Low attrition rate as the data on the outcomes were obtained for 82-86% of the original sample, and follow-up rates were similar for both treatment and control groups.
• The study measured outcomes for all mothers and children that were originally assigned to the nurse-visited treatment group regardless of how long they participated in the program.
• The children's mental development and language skills were measured through assessments whose reliability and validity are well-established, such as the Preschool Language Scales-3.
• The research staff administering these assessments and outcomes were blind to the group assignments.

  Advancement in prevention science

National Prevention Science Coalition

Society for Prevention Research

Washington State Institute for Public Policy

Blueprints for Violence Prevention

Social Research Unit

Social Development Research Group