Happiness matters. People value happiness more than material possessions ^{Reference Diener, Oishi and Columbus2} and being happy is associated with greater health, higher earnings and a longer life. ^{Reference Graham3} In Bhutan, gross national happiness has been a key element in the country's economic planning since the 1970s. ^{Reference Ura4-Reference Bok6}

The pursuit of happiness also matters. In June 1776, the Virginia Declaration of Rights outlined ‘certain inherent rights’, which include ‘the enjoyment of life and liberty, with the means of acquiring and possessing property, and pursuing and obtaining happiness and safety’. ^{Reference Hunt and Norton7} The following month, the US Declaration of Independence declared:

Studies on happiness and related factors

In recent decades, systematic study of the social and psychological correlates of individual happiness has shown that happiness is associated with a range of specific circumstances, including a stable family upbringing, being employed, good physical and mental health, personal freedom and personal values, including religious belief. ^{Reference Layard8} Happiness is related to income in a more or less linear fashion, but whereas extreme poverty is generally incompatible with happiness, increases in income above US$20 000 per head (adjusted for purchasing power parity) produce minimal incremental happiness. ^{Reference Marmot9}

The relationship between happiness and age is complex, with some evidence suggesting that it is U-shaped, namely that happiness declines as mid-life approaches but increases in later life. ^{Reference Blanchflower and Oswald10} This relationship is not entirely clear, however, as the U shape is not apparent in studies which do not use controls. ^{Reference Lelkes11} Some research identifies a peak in happiness at 65 years ^{Reference Mroczek and Spiro12} and there is significant evidence to suggest that changes in happiness through the life cycle relate to changing preferences and circumstances rather than age per se. ^{Reference Lelkes11}

It is clear, however, that individual happiness is strongly related to the happiness of others: a 20-year follow-up study by Fowler & Christakis ^{Reference Fowler and Christakis13} demonstrated identifiable clusters of happy and unhappy people within a larger social network and showed that individuals who are surrounded by happy people or are at the centre of happy networks are more likely to become happy in the future. Finally, happiness is associated with genetic inheritance and although this association is both substantial and robust, it is as yet poorly understood. ^{Reference Layard8}

The roles of mental health professionals in enhancing happiness

Psychiatrists and other mental health professionals are in daily contact with people who are unhappy as a result of mental illness and various forms of psychological distress. On this basis, one of the key contributions psychiatrists can make to increasing human happiness is through effective treatment of mental illness. This may involve direct delivery of care, supervision of treating teams, working with managers to improve services, or advocating for mental healthcare that is accessible, acceptable to individuals and reflects the evolving evidence base for various interventions, as well as patient choice.

In relation to depression and anxiety, recent years have seen increased emphasis on the role of psychological therapies in reducing symptomatology, increasing wellness and helping people back to work. These interventions are both therapeutic and cost-effective. Lord Layard points out that a course of psychological treatment for anxiety or depression costs approximately £ 750 and, as well as reducing the individual's troubling symptoms, greatly increases the possibility of a return to work, resulting in an average increased economic output of £1880 per person within 2 years. ^{Reference Layard19} As a result, this particular form of mental healthcare will reduce the individual's symptoms, pay for itself within 2 years and increase economic output.

Against this background, along with long waiting lists for evidence-based psychological therapies and a need to increase patient choice, the National Health Service (NHS) developed a dedicated Improving Access to Psychological Therapies (IAPT) programme (www.iapt.nhs.uk), which trains ‘psychological well-being practitioners’ and provides free psychological therapy in accordance with guidelines from the National Institute for Health and Clinical Excellence (NICE) at IAPT centres throughout England. Initiatives such as this are far from simple, however, and there is likely to be a steep learning curve before they are optimally effective - if they prove lastingly effective. Long-term empirical evaluations of programme outcomes are both necessary and eagerly awaited, and should help inform similar policy initiatives elsewhere. It is clearly imperative that such initiatives be matched by proportionate and complementary developments in primary care and secondary mental health services, so as to create a ‘joined-up’ service that is effective, efficient, even and coherent.

The roles of the individual

Several of the recently identified correlates of happiness are not amenable to purposive change at individual level; these include genetic inheritance and one's own upbringing. Other correlates of individual happiness appear more amenable to change: an awareness of the role of good physical and mental health, for example, may lead to changes in lifestyle and outlook which may increase happiness. An awareness of the importance of happy communities may help the individual to optimise the social circumstances in which their future happiness is to evolve.

Individuals may also benefit from an awareness of the importance of personal values and this may lead to useful psychological or behavioural changes. Such changes are most likely to optimise happiness and satisfaction when they relate to personal (often universal) values (e.g. being a good parent, partner, doctor, scientist) and involve behavioural activation in accord with what matters to the individual (i.e. valued directions), consistent with the approaches of many cognitive-behavioural therapists and psychological well-being practitioners. Such changes may focus on individuals facing issues they are avoiding, accepting a certain amount of suffering and not simply pursuing pleasure (which may be a form of avoidance and create long-term problems). Some of these approaches may also prove to be useful transdiagnostic interventions across mental disorders.

Happiness and income

Increasing individual happiness by addressing financial situations is a more complex matter. Although there is strong evidence associating happiness with increasing income (at least to a certain point), it appears that relative income may be even more important. Solnick & Hemenway ^{Reference Solnick and Hemenway20} demonstrated that a majority of people would choose an annual salary of US$50 000 when other people are receiving US$25 000, compared with US$100 000 when others are receiving US$200 000. At an individual level, then, it is reasonable to advise against comparing one's income with those of others, in the interests of happiness. There is, however, a strong human tendency to compare oneself with others (in terms of attractiveness, wealth, ability) and this may reflect an evolved safety strategy, by which one knows where one stands in relation to others before engaging with them. Addressing this tendency to compare may call for a more sophisticated psychological intervention than simple advice and may require cognitive reframing, reorientation to valued directions and behavioural modification.

The roles of government

Notwithstanding increasing governmental interest in individual happiness, ^{Reference Bok6} the literature to date provides robust support for just two ways in which governments may increase happiness: deepening democracy and providing effective physical and mental healthcare.

Do what you can. Then stop

Happiness research points to several strategies which may increase happiness:

1. • psychiatrists and other mental health professionals may increase happiness by delivering and promoting effective, evidence-based mental healthcare, informed by patient choice

2. • individuals may increase their own happiness by optimising physical and mental health; recognising the importance of personal values and happy communities; and optimising their financial situation, with an awareness that increasing income does not increase happiness infinitely and comparison with others is likely to decrease happiness

3. • government may increase happiness by deepening democracy and providing effective physical and mental healthcare.

Once these measures are understood and implemented, it is important to recognise that guidance on interventions systematically to increase happiness have probably reached the limits of current empirical knowledge. There is, moreover, a paucity of evidence to demonstrate that all of the above interventions will truly increase happiness: demonstrating correlations is certainly an important step, but it is just the first step; the next steps are to design, implement and test specific interventions.

Given the extraordinary enthusiasm that governments increasingly show for happiness research, ^{Reference Bok6,Reference Hall34,Reference Stiglitz, Sen and Fitoussi35} there is a danger that governmental interventions aimed at increasing happiness may extrapolate research findings beyond a reasonable point. Although some of the interventions suggested in this paper and elsewhere (e.g. deepening democracy) may have other benefits to justify their costs (e.g. better representation, increasing social capital), interventions with the sole aim of increasing happiness require a much stronger evidence base to justify their implementation for this aim alone.

It is especially important that the emergent political literature on happiness clearly articulate the limits of potential governmental intervention and the strong individual dimension to the pursuit of happiness. Creating optimal general social conditions conducive to happiness would appear to be the most reasonable focus for government policy in this regard: even the United States Declaration of Independence did not articulate a right to happiness itself, but rather, a right to ‘the pursuit of Happiness’ - and this is something that government can play an important role in facilitating at societal level. On this basis, there may be certain strategies (e.g. revising educational curricula to include cognitive skills conducive to well-being) which merit government support, provided there is evidence of effectiveness. ^{Reference Foley36} Such initiatives might also be consistent with the current UK government's concept of the ‘Big Society’, which seems to focus on empowering individuals and communities and reinvigorating civic society. ^{Reference Jordan37,Reference Norman38}

The manner in which the pursuit of happiness is conducted at individual level is, by contrast, an intensely individual matter and there is little role for government at this level. In addition, some individuals may choose not to seek out happiness in an explicit fashion, preferring simply to engage in such diverse activities as deepening skills, developing passionate interests, pursuing hobbies, building a career, committing to religion, engaging in education, composing poems, admiring flowers, sitting quietly and discovering relationships. These activities may not be undertaken with the express desire to increase happiness, but may, in words commonly attributed to American writer Henry David Thoreau, quietly open the door to greater happiness: ‘Happiness is like a butterfly: the more you chase it, the more it will elude you, but if you turn your attention to other things, it will come and sit softly on your shoulder.’ ^{Reference Malik39}

There is also the matter of human nature to be considered: regardless of social factors such as democratic governance and equality of income, people behave in individual, idiosyncratic and unpredictable fashions, which may, on occasion, appear egocentric, flawed and illogical to others. In addition, countries commonly seen as the most egalitarian and socially ordered (e.g. Scandinavian countries) tend to have the highest suicide rates, ^{Reference Kelly, Davoren, Ní Mhaoláin, Breen and Casey40} despite relatively high ratings for individual happiness; ^{Reference Doherty and Kelly18} this ‘happiness/suicide paradox’ merits further study. The recent initiative from the UK Office for National Statistics to consider how best to measure well-being is a useful first step in this direction. ⁴¹

At the level of the individual, however, government needs to recognise the limits of central intervention in relation to happiness and, at a certain point, in the words of Chinese poet Lao Tzu: ^{Reference Mitchell42}