Adolescence has long been characterized by risky behaviors that sometimes have disastrous consequences. Dressing provocatively, driving too fast or experimenting with drugs and alcohol are only a few of the ways that teens engage in behaviors that can get them into serious trouble. The question remains, why do teenagers engage in such risky activities? Though cultural factors and peer pressure likely play a role, the neuroscience of the developing teenage brain also provides interesting insight into why teens often get themselves into precarious situations.
The brain does not develop evenly across all levels and structures. This can be problematic at various life stages because different regions of the brain help to process information whereas other areas are more involved in direct action. For example, reward-pleasure centers tend to be situated deep within the brain. However, parts of the brain such as the frontal cortex, which is responsible for making complex decisions and planning for various possible outcomes, are located higher up in the brain. So, if the various areas of the brain develop at different rates during the teenage years, it is possible that the ability to weigh out consequences of actions is compromised.
The nucleus accumbens is a region of the brain directly involved in the reward-pleasure center. This means that the accumbens responds to actions that may result in pleasure or reward to the system. A study in 2006 conducted at the The Sackler Institute for Developmental Psychobiology in New York looked at the impact of the fact that the accumbens develops earlier than higher cortical structures on teenage behavior. Thirty-seven participants (7–29 years of age) were scanned using functional brain imaging and a paradigm that parametrically manipulated reward values. The results show exaggerated accumbens activity, relative to prefrontal activity in adolescents, compared with children and adults, which appeared to be driven by different time courses of development for these regions. Accumbens activity in adolescents looked like that of adults in both extent of activity and sensitivity to reward values, although the magnitude of activity was exaggerated. In contrast, the extent of orbital frontal cortex activity in adolescents looked more like that of children than adults, with less focal patterns of activity. These findings suggest that maturing subcortical systems become disproportionately activated relative to later maturing top–down control systems, biasing the adolescent’s action toward immediate over long-term gains (Galvan, Hare, et al, 2006). So, the teenage brain may engage in risky behavior simply because the structures that help engage in thinking through and understanding consequences are not as developed as those seeking immediate reward and pleasure.
Given the biological challenges facing teens, it is important that parents understand what factors can assist in preventing overly risky behaviors. A study published in the Journal of American Medicine examined the various factors that influence teens. Resnick, Bearman et al interviewed over 10,000 teenagers. Eight areas were assessed: emotional distress; suicidal thoughts and behaviors; violence; use of 3 substances (cigarettes, alcohol, marijuana); and 2 types of sexual behaviors (age of sexual debut and pregnancy history). Independent variables included measures of family context, school context, and individual characteristics. The analysis of their results revealed that parent-family connectedness and perceived school connectedness were protective against every health risk behavior measure except history of pregnancy. Conversely, ease of access to guns at home was associated with suicidality and violence. Access to substances in the home was associated with use of cigarettes, alcohol, and marijuana use. Repeating a grade in school was associated with emotional distress among students in junior high and high school and with tobacco use among junior high students. On the other hand, parental expectations regarding school achievement were associated with lower levels of health risk behaviors (Resnick et al, 1997).
So, though teens may have neurodevelopment stacked against them to certain degree, parental support can make a meaningful difference. Family and school contexts as well as individual characteristics are associated with health and risky behaviors in adolescents. Parents need to beware of the first steps in preventing overly risky behaviors.
Earlier Development of the Accumbens Relative to Orbitofrontal Cortex Might Underlie Risk-Taking Behavior in Adolescents; Adriana Galvan, Hare, et al, 2006. The Journal of Neuroscience.
Protecting Adolescents From Harm: Findings From the National Longitudinal Study on Adolescent Health; Resnick, Bearman, et al, 1997. The Journal of the American Medical Association.