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| What's Killing Our Kids? Expert discusses puberty and risk-taking behavior in adolescents |
| The primary causes of death and disability among adolescents are problems of emotion and behavioral control, says Ronald Dahl, M.D., Professor of Psychiatry at the University of Pittsburgh School of Medicine. "It includes accidents, suicide, homicide, depression, alcohol and substance use, violence, reckless behaviors, eating disorders, health problems related to risky sexual behaviors, you can go on and on," explains Dahl. Dahl adds that the high rates of risk-taking, sensation seeking and erratic, emotionally influenced behavior contribute a lot to the enormous consequences. Dahl made his remarks at the 2003 Lipsitt-Duchin Lecture Series at Brown University that addressed the topic, "What's Killing our Kids? Behavioral Misadventures." "In many ways, adolescence is the healthiest and most resilient period of the lifespan," says Dahl. "Typically, almost everything you can measure improves between childhood and adolescence - strength, speed, reaction time, reasoning abilities, immune function, increased resistance to cold, heat, hunger and dehydration and most types of injury. And yet, when we go from middle-school age to late adolescence to early adulthood, overall morbidity and mortality rates increase by 200 to 300 percent. While these problems in adolescence have been recognized throughout human history, the critical questions remain: Are the changes based in biology? Are they based in the hormones of puberty? Are there specific brain changes that underpin some aspects of risk-taking, sensation-seeking and the emotional changes at puberty? Defining adolescence What is adolescence? Dahl says the modern study of adolescence really began in 1904 by G.S. Hall, who wrote about adolescence as a period of heightened "storm and stress." Not until the 1960s and 1970s did anyone look at the biologic underpinnings of adolescence. Even then, researchers and clinicians had only a narrow understanding of hormones and explained the problems of adolescence as due to "raging hormones." "I not only think it's oversimplifying the situation, I think it's overstating the situation," says Dahl. "Many, perhaps most, adolescents navigate this interval with minimal difficulties. They do quite well actually." However, Dahl adds, there is strong empirical evidence for some aspects of this metaphor of storm and stress, the first being increased conflict with parents. "What happens is a function of puberty," says Dahl. "It's not that they are more likely to argue, but the intensity of emotion is much higher. At puberty at best, when conflicts arise, it's more likely to catapult into a higher state." The second major area is mood volatility. The third is increased risk-taking, recklessness and sensation-seeking. "They are actually seeking out, wanting situations and experiences that evoke strong emotions and intense feelings," says Dahl. "This really seems to be a part of this period of time." Defining adolescence is not as simple as calling it the teenage years, Dahl says, nor can it be defined simply in biologic terms. Adolescence, he says, is that awkward period between the beginning of sexual maturation and the attainment of adult roles and responsibilities. It is the transition from child status, which by definition requires some level of adult monitoring, to adult status where one has self-responsibility for behavior. This developmental interval encompasses the body and brain changes of puberty. Adolescence consists of several component processes, says Dahl. It is a time of rapid physical growth and sexual maturation; it's a time when the secondary sexual characteristics that accompany becoming reproductively mature occur; a time of profound motivational and emotional changes; a time of much cognitive development in the sense of measuring cognitive abilities; a time when there is a maturation of judgment and self-regulation skills; and, there are brain changes linked to each component. "It's really a suite of changes with relative synchrony," says Dahl. Changes in pubertal maturation Research data from Finland, Sweden, Norway, Italy, UK, and the United States, show that from 1860 to 1960 the age of menarche changed from about 15 and half years on average to about 13 years in 1960. An epidemiologic study (1977) of 17,000 European-American and African-American girls in United States pediatric practices found that at age seven, 7% of the European-American girls and 27% of the African-American girls were already into the first stage of puberty. By eight years of age, the figures rose to 15 % and 47%. Physicians trained in using the Tanner Stage 2 rating gathered this data, which involves a physical exam to monitor breast and pubic hair development. "So when we talk about these adolescent brain changes, we're not talking about the late teenage years," Dahl says. "Some of these changes are beginning to occur for a lot of kids, by seven, eight, nine, and 10 years of age." Now, the average age of menarche is 12. In 1970, the timing of first marriage in the U.S. was 21 for women and 23 for men. By the 2000 census it changed to 26 for women and 27 for men. "It's not simply attitudes about marriage that are changing," says Dahl. "Many adult roles- starting careers, owning a home, choosing to become parents -parents are now occurring a decade or more after the physical changes of puberty." In a relatively brief period, adolescence has expanded from a 2- to 4- year interval in traditional societies, to an 8- to 15-year interval in contemporary society. "These historical changes in adolescence have major implications regarding brain development," says Dahl. "We're very early in the curve of beginning to understand what goes specifically with puberty and what doesn't," Dahl says. What are the implications of these changes? What is happening to more traditional aspects of cognitive development if some aspects of the brain systems are being activated earlier, and the igniting passions and the strong motivations are happening earlier? "Here, we go to the other end of the spectrum," Dahl says. "That is that most measures of cognitive development correlate with age and experience, not sexual maturation. If you look at the ability to think logically, plan, and reason, that is what really seems to occur." "It's no surprise. If you work in a clinic and you have a 12-year-old boy who is completely pre-pubertal and a 12-year-old boy who looks like he's a completely developed man, you wouldn't expect one to be better at playing chess or doing algebra, says Dahl. "There is no correlation with most traditional measures of cognitive development with pubertal maturation." Dahl uses the metaphor of starting the engines without a skilled driver. "What's been happening over the past 100 years is that there has been a shift to an earlier timing of puberty which results now in several years... with a sexually mature body, sexually activated brain circuits. Yet there is a relatively immature set of neurobehavioral systems necessary for self-control, for affect regulation, for emotional intelligence. This is going to require not only the brain developmental processes that continue on into late adolescence in the early 20s, but the set of experiences that sculpt and shape those abilities and those skills. "The prediction is that one would see an increased risk for disorders of self-control and difficulties navigating complex social-emotional situations. And I think the evidence is pretty compelling that's what's been happening," Dahl says. The other part of the equation that should not be forgotten, says Dahl, is that while kids are developing and refining their abilities for self-control and emotion regulation, a set of systems should be in place. Parents and other adults can monitor and gradually withdraw the amount of monitoring needed while these skills develop. In addition, there is not a coherent approach about how we should regard adolescent decision-making capabilities in our society. There is no coherence in terms of how we should set policies. "Why is it in this country that people can't drive until they are 16, can't vote and make most adult decisions until they are 18, can't drink alcohol until they're 21 and can't rent cars from a commercial agency until age 25?" Dahl asks. "And yet, you can stand trial for murder at age 13 in many states." The other side of this coin is that not only is adolescence a period of enormous vulnerability, says Dahl. It's an interval of enormous opportunity. It's a time when kids can become intensely motivated to pursue higher goals of all sorts, says Dahl. He adds that we need to give a great deal of thought to who is influencing our adolescents' passions. "Certainly, the people who market products understand this is an interval of time to develop brand loyalty and align behaviors in ways that serve economic interests," concludes Dahl. "But I think we need to give a lot more thought to this interval of time in terms of the broader issues in health consequences and think about the ways in which we can develop healthier versions of these igniting passions and motivations." References Herman-Giddens ME, Slora EJ, Wasserman RC, et al.: Secondary sexual characteristics and menses in young girls seen in office practice: a study from the Pediatric Research in Office Settings Network. Pediatrics, 99(4):505-512; 1997. Tanner, JM: Foetus into Man, Second Edition. Castlemead Publications; 1989. |