At what age is a child considered an adolescent?

Age Definition of Adolescence

Adolescence is typically defined as the period between ages 10 and 19 years, though an expanded definition of 10-24 years more accurately reflects contemporary developmental patterns and social transitions.

Official Definitions and Age Ranges

• The World Health Organization (WHO) and the United Nations define adolescents as individuals between the ages of 10 and 19 years 1, 2
• Youth are defined by the WHO and United Nations as individuals in the age grouping of 15 to 24 years old 1
• Young people is a broader term that encompasses both adolescents and youth, covering the age range of 10 to 24 years 2
• The Guidelines for Adolescent Depression in Primary Care (GLAD-PC) use an age range of 10 to 21 years for adolescents, recognizing that this encompasses preteenagers, adolescents, and young adults 1

Developmental Considerations

• Adolescence is characterized by rapid and profound physical, intellectual, emotional, and psychological changes that mark the transition from childhood to adulthood 3
• Physical development varies between individuals of the same age, and children with chronic diseases may develop autonomy later than their peers 1
• There is a notable decline in physical activity as children transition from childhood to adolescence, marking a behavioral shift during this period 1
• The transition from childhood to adolescence involves incremental shifts in knowledge and decision-making from parents to the adolescent 1

Contemporary Understanding of Adolescence

• Recent research suggests that an expanded definition of 10-24 years corresponds more closely to adolescent growth patterns and popular understanding of this life phase 4
• Earlier onset of puberty has accelerated the beginning of adolescence in nearly all populations, while continued growth extends into the 20s 4
• Delayed timing of role transitions, including completion of education, marriage, and parenthood, have shifted perceptions of when adulthood begins 4

Clinical Applications of Adolescent Age Definitions

• For clinical purposes, healthcare providers may choose to use either adult or adolescent guidelines for individuals between 18 and 21 years based on the developmental status of the adolescent 1
• Adolescent medicine clinicians and school health clinicians often see patients until they are 21 years old, extending the practical definition of adolescence in healthcare settings 1
• Guidelines for various health conditions, including depression and diabetes, specifically identify adolescents as a distinct group requiring age-appropriate care approaches 1

Common Pitfalls in Defining Adolescence

• Overlapping age groupings in guidelines can create ambiguity in their application (e.g., some guidelines use 0-5 years and 5-17 years, creating confusion about which guidelines apply to 5-year-olds) 1
• Using subjective categories like "school-aged children" rather than specific age ranges can lack clarity for end-users 1
• Terms such as "young people" or "youth" are sometimes used interchangeably but have specific definitions that may not accurately reflect the intended age group 1
• Cultural and social differences may affect the timing and perception of adolescence, requiring flexibility in applying age-based definitions 1, 4