The National Youth Survey, involving the Institute of Behavioral Science (IBS) and the Institute of Behavioral Genetics (IBG), is a major intergenerational and life course study that is searching for the answers to these questions. Initial data collection began in 1976 on 1,725 adolescents, 11 to 17 years of age, and their parents, who were selected as a representative sample of the U.S. population. The adolescents answered questions regarding their families, environments, attitudes, alcohol use, criminal behavior, and drug use.

“The goal of this study at first was to discover what environmental factors such as school attendance and strength of family relationships may affect adolescent attitudes and behavior,” said Scott Menard, coprincipal investigator on the project and research associate at IBS. “Data were again collected from the respondents in 1992, when the respondents were 27 to 33 years old, to track life course trajectories that put some people on the path to problem behaviors.”

A new phase of the study, which received a $6.8 million grant from the National Institute of Alcohol Abuse and Alcoholism and the Office of Behavioral and Social Research, will involve interviewing the original respondents, now in their 30s and 40s, their parents, and also the spouses and children of the original respondents. For the first time DNA samples will be collected from these individuals to study the heritable transmission of problem behaviors.

“The collaboration of IBS and IBG is probably unique in the country in trying to understand to what extent environment and genetics together play a role in determining whether an individual will adopt a pattern of problem behaviors, “ said Michael Stallings, project coinvestigator, assistant professor of psychology, and research fellow in IBG. “We know some environmental factors such as broken families, contribute to risk, but the environmental factors so far identified can’t fully explain persistent problem behavior. Some people in unsupportive environments show a resiliency to such behavior. We think a combination of learned experiences and heritable traits may explain individual differences.”

One of the outcomes of this research might be the ability to give future generations ideas about how to make informed decisions about their behavior. These researchers agree that it is neither environment nor genetics alone that determines the life course of an individual. Understanding the environmental risks as well as the genetic risk a person may carry for behavioral problems, might help individuals modify their environments in ways that reduce the risks of genetic vulnerabilities affecting their lives.