Every wealthy nation is facing an epidemic of depression, Martin Seligman, the internationally renowned expert on positive psychology, told a major conference in Glasgow this week.
Among a range of actions that could be undertaken to break the cycle of pessimism, Professor Seligman suggested that schools take steps to use positive psychological strategies with pupils. His views received a cautious welcome from some educationists present.
Professor Seligman told those participating in the Vanguard programme, a two-day meeting organised by the new Centre for Confidence and Well-being, that pessimism was growing among young people and that the school curriculum needed to take on board issues such as learning "realistic optimism". Depression was 10 times as common as 50 years ago, he said.
While the average age for the onset of depression used to be 29.5 years, it was now 14.5 years. Depression was a disease of puberty, he said. The reasons were neither biological nor environmental. "This is a modern society phenomenon," Professor Seligman said.
Causes included the fact that individualism was at an all-time high - the "big I and the small we". Our grandparents' generation, on the other hand, had had a spiritual consolation to draw on and a belief in community and the extended family.
"All these things have been eroded," he said. "The spiritual furniture that our young people have to sit on when they fail is threadbare".
Professor Seligman also blamed "victimology" - the tendency to blame other people when things go wrong - as another underlying cause of depression.
Alongside that was the modern tendency to take short cuts. "One of our great weapons against depression is to know what our strengths are and then use them as much as possible in our lives," he commented. "The taking of short cuts may save you time but it also sets you up for depression."
Professor Seligman said he and his team at the University of Pennsylvania were working with 10-14s at risk of depression, and believe they are making progress. Among the strategies they use are assertiveness, negotiation, relaxation, creative problem-solving and decision-making.
In a research exercise which has yet to be published, his team will also reveal lessons from positive psychology. For instance, when pupils are studying William Golding's Lord of the Flies, teachers could ask them to think of 15 kind things and write them down; or teachers could conduct a lesson on love while teaching Romeo and Juliet.
While Professor Seligman's ideas were warmly received, there was a feeling that many Scottish schools were already practising methodologies designed to make young people positive and ambitious in their outlook.
Paul McLaughlin, headteacher of St Ninian's High in Kirkintilloch, one of the first 20 Schools of Ambition, said: "Schools try pretty hard on this agenda. What is helpful is the possibility of more practical strategies."
Andy Mimnagh, headteacher of St Mungo's High in Falkirk, taking the example cited by Professor Seligman of Lord of the Flies, said he would expect an English teacher to use the idea of the darkness of man's soul and show the more positive sides too.
But Mr Mimnagh cautioned against introducing positive psychology programmes, saying: "Schools are programmed out. We do need to show that an individual teacher in his or her own classroom can make a difference."