ASU research helps prevent substance abuse, mental health problems and more
Over the past 20 years, science-based interventions and treatments using a statistical method called mediation analysis have contributed to reduced rates of smoking and drinking among teenagers and young adults in the U.S. Research from Arizona State University has developed these statistical techniques, which save time and money and are now used widely in psychology, sociology, biology, education and medicine. Many of available medical treatment options are the result of clinical trials that used mediation to figure out what worked. Image by Duy Pham/Unsplash
Smoking rates among teenagers today are much lower than they were a generation ago, decreasing from 36% in the late 1990s to 9% today. The rates of alcohol consumption among underage drinkers have also decreased. At the turn of the century, people aged 12–20 years drank 11% of all the alcohol consumed in the U.S. Today, they only drink 3%.
These decreases are in part the result of science-based interventions that were designed to prevent substance use. But these interventions would not have been possible without statistical methods, including a statistical method called mediation analysis that lets researchers understand why an intervention or treatment succeeds or fails. Mediation analysis also identifies how aspects of a substance use reduction program or medical treatment cause its success.
About this story
This ASU research was possible only because of the longstanding agreement between the U.S. government and America’s research universities.
That agreement provides that universities would not only undertake the research but would also build the necessary infrastructure in exchange for grants that fund both the research and construction cost recovery.
That agreement and all the economic and societal benefits that come from such research have recently been put at risk.
Prevention makes our lives better — and it saves money. Though smoking and drinking rates among adolescents are on the decline, there is still room for mediation analyses to save the U.S. more money. According to the National Institute on Alcohol Abuse and Alcoholism, misusing alcohol costs the U.S. $249 billion. The Centers for Disease Control and Prevention report that cigarette smoking costs the U.S. around $600 billion, including $240 billion in health care spending and over $300 billion in lost productivity from smoking-related deaths and illnesses.
David MacKinnon, Regents Professor of psychology at Arizona State University, has been studying and using mediation analyses for the past 35 years because of the many practical applications — and because they work really well.
“I like using science and math to address serious health problems like smoking, drug abuse and heart disease,” MacKinnon said. “Mediation analyses let us extract a lot of information from data and have the promise of identifying mechanisms by which effects occur that could be applicable to other situations.”
Unlike a third wheel, third variables are crucial — and causal
There are many paths to a teenager ending up struggling with substance abuse. They might struggle with impulsivity in general — or they might have parents who fight often, or maybe their friends get drunk most weekends.
Because there is more than one way to connect risk factors to substance use, scientists often have to take an indirect path that considers variables like parenting style or peer influences.
“Most research looks at the relationship between two variables — like risk-taking and substance use — but there can be a lot happening in between, and those 'third variables' can cause the outcome,” MacKinnon explains.
Long-lasting impacts
Adolescents who experiment with drugs and alcohol at a young age are more likely to develop lifelong substance abuse problems. A psychology department research team led by Nancy Gonzales, executive vice president and university provost, used mediation to create a program that decreases alcohol use in teenagers who started drinking at a young age.
The program brought families to their child’s school for a series of interactive sessions. Each session taught a skill, such as good listening practices or strategies for talking about difficult topics, and parents and students practiced as a family. Just spending 18 hours in the program produced protective effects against teenage alcohol misuse that lasted at least five years. By their senior year, kids who had participated in the program as seventh graders were drinking less.
This reduced alcohol consumption is important because even small reductions in adolescent drinking can have a cascade effect on other public health problems like alcoholism and drug abuse disorders, risky sexual behavior and other health problems.
Helping children of divorce
Close to half of all marriages in the U.S. end in divorce, affecting over 1 million children each year. These children are at an increased risk of struggling in school, experiencing mental health or substance use problems and engaging in risky sexual behavior. Mediation analyses have shown that a lot of these risks stem from conflict between divorced or separated parents, which creates fear of abandonment in children and contributes to future mental health symptoms.
Prevention scientists working in ASU’s Research and Education Advancing Children’s Health Institute leveraged decades of work using mediation to create an online parenting skills program for separated or divorced couples. The program reduces interparental conflict and decreases children’s anxiety and depression symptoms.
Read more on ASU News here and here.
The answers to ‘why’ and ‘how’ questions save time and money
How much do school-based prevention programs decrease teen vaping rates? Why do monetary incentives and mobile clinics increase local vaccination rates?
Answering “how” and “why” questions like these require scientists to figure out what exactly caused a decrease in teen vaping or the reasons that caused more people to roll up their sleeves and get vaccinated. Causation can happen in many ways and can even be indirect, and mediation can accurately find the cause.
Mediation analysis strategies MacKinnon has developed are now used widely, in medicine, psychology, sociology, biology and education. And, many of the treatment options our doctors can offer us are possible because of clinical trials that used mediation to figure out what worked.
Mediation analysis lets researchers pull more information from scientific studies, which is why the National Institutes of Health recommends research proposals include a section evaluating why and how treatments or interventions work.
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