An article published January 17, 2018, in the journal lancet Child & Adolescent Health has said that rather than age 10–19 years, a definition of 10–24
years corresponds more closely to adolescent growth and popular understandings of this life phase. This new definition reflects the changing patterns, both biologically as well as socially, because of lifestyle changes.
“Although many adult legal privileges start at age 18 years, the adoption of adult roles and responsibilities generally occurs later. An expanded and more inclusive definition of adolescence is essential for developmentally appropriate framing of laws, social policies, and service systems”, say the authors.