Brazilian supermodel Gisele Bündchen revealed recently that before going to sleep she mentally ticks off the things for which she is thankful. This must be a cumbersome exercise: the long-limbed beauty is the world’s highest-paid clothes horse; is married to a rich, handsome American football star ; she has two gorgeous children; features in Forbes’ annual power list; and, in her spare time, is a UN goodwill ambassador for the environment.

She is obviously clued up about happiness research, too, which extols the benefits of counting one’s blessings — usually in a “gratitude journal”. This kind of ledger is bound to figure in a series of evening classes launched this week across the UK by a group called Action for Happiness. The six-week self-improvement course, endorsed by the Dalai Lama, claims to harness the science of happiness, which has charmed its way into policymaking.

Also this week, the Office for National Statistics published its geographical league table of personal wellbeing in the UK, compiled by quizzing 165,000 people on how satisfied they are with life. Fermanagh in Northern Ireland is the jolly table-topper; London is steeped in melancholy. Since the ultimate goal in life for most people is to be happy, the logic goes, governments should find ways of increasing civic contentment.

But the science of wellbeing has turned out, over the past 15 years, to be a keenly disputed field of psychology whose practitioners have struggled to elucidate the nature of nirvana, let alone put numbers to it. Meanwhile, happiness has become a central issue in public health. A 2014 study of 3,000 older people, led by Professor Andrew Steptoe at University College London, found that participants who said they enjoyed life saw a slower rate of physical decline than their curmudgeonly peers , even taking into account other factors such as income, smoking and drinking.

Scientists have been hunting the precise mechanism through which a positive state of mind exerts a beneficial effect on our biology. Barbara Fredrickson, a psychology professor at the University of North Carolina, published a startling paper in 2013 suggesting that the genomic profile of deeply contented people differed measurably from those of others, possibly influencing function. The finding provoked publicity and then controversy; one reanalysis using Prof Fredrickson’s data failed to reach the same conclusion.

None of which should stop us from trying to discern the elements of a happy life. This is the goal of the Greater Good Science Center at the University of California, Berkeley, which combines on happiness with practical recommendations. It defines happiness as “the experience of joy, contentment, or positive wellbeing, combined with a sense that one’s life is good, meaningful and worthwhile”. Contentment stems not from material wealth, as the rich keep reminding us, but from relationships and personal development. Compassion and altruism seem central.

And this is, perhaps, the most helpful pointer furnished by science: true happiness is rarely a succession of immediate, individual pleasures, such as sex, drugs and chocolate. Indeed, many experiences deemed enriching — raising children, mastering an instrument, donating a kidney — require pain and sacrifice. Happiness appears to be linked to living a life of purpose and meaning; the ONS survey now asks residents whether their lives feel worthwhile.