Adolescence is the phase of life between childhood and adulthood, from ages 10 to 19. It is a unique stage of human development and an important time for laying the foundations of good health.

Adolescents experience rapid physical, cognitive and psychosocial growth. This affects how they feel, think, make decisions, and interact with the world around them. 

Despite being thought of as a healthy stage of life, there is significant death, illness and injury in the adolescent years. Much of this is preventable or treatable. During this phase, adolescents establish patterns of behaviour – for instance, related to diet, physical activity, substance use, and sexual activity – that can protect their health and the health of others around them, or put their health at risk now and in the future.

To grow and develop in good health, adolescents need information, including age-appropriate comprehensive sexuality education; opportunities to develop life skills; health services that are acceptable, equitable, appropriate and effective; and safe and supportive environments. They also need opportunities to meaningfully participate in the design and delivery of interventions to improve and maintain their health. Expanding such opportunities is key to responding to adolescents’ specific needs and rights. 

There are more adolescents in the world than ever before: 1.2 billion, totalling one sixth of the global population. This number is expected to rise through 2050, particularly in low- and middle-income countries where close to 90% of 10- to 19-year-olds live.

An estimated 1.1 million adolescents die each year. The leading causes are road traffic injuries, suicide and interpersonal violence. Millions of adolescents also experience illness and injury. Causes of mortality and morbidity among adolescents differ by sex and age, and also by geographic region. 

For 10-14-year-olds, the leading risks for health are related to water, hygiene and sanitation. Risks for 15-19-year-olds are more often related to behaviours, such as alcohol use and unsafe sex. Poor diet and low physical activity are additional challenges which begin in childhood and adolescence, as does sexual abuse. Older adolescent girls are disproportionately affected by intimate partner violence. Pregnancy complications and unsafe abortions are the leading causes of death among 15-19-year-old girls.

Most adolescent mortality and morbidity is preventable or treatable, but adolescents face specific barriers in accessing health information and services. Restrictive laws and policies, parental or partner control, limited knowledge, distance, cost, lack of confidentiality, and provider bias can all restrict adolescents from getting the care they need to grow and develop in good health.

WHO supports countries to ensure that their national adolescent health responses are evidence-based and take account of the values and preferences of adolescents. 

Improving the evidence base on adolescent health is crucial. WHO supports countries to improve measurement and  strengthen data, conducts research, and shares best practice. 

WHO issues evidence-based recommendations that are relevant for – or specific to – adolescents across the full range of health areas including: positive development, communicable diseases, non-communicable diseases, sexual and reproductive health including HIV, unintentional injury, violence, and mental health, substance abuse and self-harm. 

To support the implementation of these recommendations, WHO produces a range of policy and programme support tools. At the heart is the Global Accelerated Action for the Health of Adolescents (AA-HA!), which guides national-level policy-makers and programme managers on how to plan, implement, monitor, and evaluate adolescent health programmes. 

WHO also supports countries to scale up efforts in service delivery, financing and governance, helps to build the capacities of national-level researchers and programmers, and provides technical support for policy and programmes.

Adolescents need protection from harm on the one hand, and support to make independent decisions on the other. They have a key role to play in the response to their own health and wellbeing. WHO's 13th General Programme of Work recognizes this and is committed to working with adolescents as central partners to improve adolescent health.