Drink and drug use by young people in Scotland has declined in the past decade, a study has revealed.
Researchers at the University of Edinburgh found the rate of smoking among 15-year-olds had fallen from 16% to 11% since 2002.
The findings are from the latest NHS-funded Health Behaviours in School-aged Children (HBSC) report.
The number of young people drinking alcohol at least once a week fell by over a third, and cannabis use halved.
Almost 7,000 pupils were interviewed for the report, which provides a picture of the wellbeing of young people aged 11, 13 and 15.
Professor Candace Currie, director of the Child and Adolescent Research Unit at the University of Edinburgh, said: "These recent findings are extremely encouraging with improvements in several areas relating to children's overall wellbeing.
"Scotland has participated in this international collaborative study for two decades giving us a unique opportunity to track key areas of health among young people and compare Scotland's progress to other countries."
Findings show eating habits have improved, with daily sweet consumption falling by a third, and consumption of crisps and chips halving between 2002 and 2010.
In the area of general wellbeing and life satisfaction, the majority of young people (87%) were satisfied with their life.
However, levels of boys' and girls' happiness and girls' confidence, which had increased in previous years, decreased since 2006.
Researchers also found more children reporting that their family was financially well off, and an increasing number of children saying they could talk to their fathers about their problems.
Rates of physical activity remained low, with 19% of boys and 11% of girls meeting the Scottish government's weekly guidelines for moderate to vigorous physical activity.
In spite of this, approximately half of young people in Scotland walk to school, and TV viewing has decreased since 2002.
Dr Gerry McCartney, head of the Public Health Observatory at NHS Health Scotland, said: "The HBSC studies provide a unique way of comparing Scottish young people to young people in other countries.
"The surveys collect a range of data on young people's health, but also data on the variety of factors in society which influence health."
The study helped shape public policy, he added.