Many mental health problems emerge in late childhood and early adolescence. Recent studies have identified mental health problems - in particular depression, as the largest cause of the burden of disease among young people (DALYs). Poor mental health can have import effect on the wider health and development of adolescents and is association with several health and social outcomes such as higher alcohol, tobacco and illicit substances use, adolescent pregnancy, school drop out and delinquent behaviours. There is growing consensus that healthy development during childhood and adolescence contributes to good mental health and can prevent mental health problems. Enhancing social skills, problem-solving skills and self confidence can help prevent mental health problems such as conduct disorders, anxiety, depression and eating disorders as well as other risk behaviours including those that relate to sexual behaviour, substance abuse, and violent behaviour. Health workers need to have the competencies to relate to young people, to detect mental health problems early, and to provide treatments which include counselling, cognitive-behavioural therapy and, where appropriate, psychotropic medication.