An obsession with happiness is having an adverse effect for those who seek it, experts say.
Over the last 30 years, the pursuit of happiness has come to define the ultimate modern goal.
Yet a new study shows levels of expectation about happiness are unreasonable and set young people up for failure.
Researchers at Yale University found that more teenagers and young people were depressed thanks to dreams of easy success and disappointment when they were not achieved, the Daily Mail reported.
Yale also found that adults who took advice on how to be happy from magazines often wound up feeling worse.
Chris Skellett, a Dunedin clinical psychologist and author of the book Happiness is not enough, said unrealistic ideas of happiness contributed to depression in New Zealand too.
"Self-help books on happiness are often either of the mindfulness approach, tranquility and calmness or they are about the pursuit of happiness.
"The word pursuit in itself implies an emphasis on success and change which is a very western approach to happiness."
He said the pursuit of happiness doctrine especially values the success of children, putting on pressure from a young age and predisposing them to the view that success is an emotional right.
Yale University's findings that young people from affluent backgrounds were more at risk applied to New Zealand too, Dr Skellett said.
He said while the post-war sense of ambition was not as strong today, family and society played a role in unfairly raising expectations.
"If you think of an upwardly-mobile family, they're more likely to have photos of little Johnny holding a trophy than playing in the dirt.
"When asked how their kids are, they're more likely to say they got into the orchestra than another kind of family, who love their kids for who they are, not what they've achieved."
He said teenagers could then become depressed because they are not getting ahead in the way they expected.
The key to happiness was a balance between pleasure and achievement, he said.
"And the end of the day it's not all about winning, some of us look back and wish we'd done more with our lives, others wish they'd spent more time enjoying the journey."