Adulthood now begins at age 24, say scientists

Most people agree that adolescence ends with the teenage years. But researchers now say adolescence should extend into the mid-20s.

That’s the main argument posed in an opinion piece in the journal The Lancet: Child & Adolescent Health. In it, a group of adolescent health experts contend that adolescence, which is the phase of life between childhood and adulthood, should stretch from 10 years of age to 24 instead of the current definition of 10 to 19.

The researchers didn’t just make these numbers up. They point out that young people are staying in school longer, as well as waiting longer to get married and have children — the last two activities often being associated with adulthood.

According to U.S. Census Bureau data, the median age at first marriage has steadily risen for men and women since the 1980s. As of 2017, the median age for men at their first marriage was 29, while the median age for women was 27. That’s a huge increase from 1980, when men were likely to get hitched at around age 23 and women at around 22.

Being an adult involves more than getting married and having kids — plenty of adults never do either — and the researchers also cited biological factors in their argument. The brain continues to mature after the age of 19, they note, and many people don’t get their wisdom teeth until their early or mid-20s.

Eugene Beresin, MD, director of the Massachusetts General Hospital Clay Center for Young Healthy Minds and a professor of psychiatry at Harvard Medical School, tells Yahoo Lifestyle that the idea that adolescence ends at 18 or 19 is pretty arbitrary. “There’s no rationale for that other than high school ends at that age,” he says. “You graduate from high school and you ‘grow up.’”

Danelle Fisher, MD, chair of pediatrics at Providence Saint John’s Health Center in Santa Monica, Calif., tells Yahoo Lifestyle that prolonging the age of adolescence is an “interesting thought.” She thinks the brain development argument is one of the strongest for changing the boundaries of adolescence. “It’s not like you get to 18 or 19 and the brain is done growing,” she says. “Those in late adolescence are still prone to some of the things that adolescents can get into trouble with, partly because their brain hasn’t fully developed. They don’t always make smart choices when it comes to their health and well-being.”

Beresin agrees. “The greatest growth in the brain is between 14 and 26,” he says. “During that period of time, the brain is driven largely by emotion and impulse. Feelings feel more intense and powerful — this is why adolescents tend to do things based on impulse”

Licensed clinical psychologist John Mayer, PhD, author of Family Fit: Find Your Balance in Life, tells Yahoo Lifestyle that he’s “absolutely in agreement” with the concept. Adolescence doesn’t end until someone “takes their place in the adult world,” which generally means they start a career and form a life separate from their parents, he argues. “This has been an extremely useful definition for me in my therapy work with adolescents and families, and has benefited parents greatly to understand this definition of the boundaries of this period of life,” he says. “Young persons’ behaviors confirm the accuracy of this definition of adolescence. We see it in them daily.”

Fisher points out, however, that some things, like staying in school for a longer time, can be the result of outside influences — namely, the economy. “Some want to stay in education longer to have better job prospects when they get out,” she says. And, while the argument to extend adolescence through age 24 makes sense for the U.S. and other developed countries, it doesn’t quite fit with countries and cultures in which it’s considered normal to begin having children in your teens.

Ultimately, it’s tough to put an exact age on when individuals will move from adolescence to adulthood. “Age is relative,” Beresin says. Still, experts largely favor extending it in adolescence.