Up to one in three boys and two in five girls report some form of psychological distress such as feeling under strain, inability to concentrate, feeling depressed or losing sleep - and figures rise during the passage to late adolescence.
A caution to teachers and others against writing off difficulties as "a phase they'll grow out of" came from Graham Bryce, a consultant psychiatrist. Substantial numbers of young people suffer serious problems, he said, and they are no more immune from the "slings and arrows" of life than adults.
Being more open about problems was an important first step in recognising and dealing with the issues.
Andy Furlong, professor of sociology at Glasgow University and author of a report on "Youth Transition and Health", believes part of the problem is that young people no longer face "clear and straightforward" choices.
"This is quite difficult to adjust to psychologically," Professor Furlong says.