Executive summary
Mental health plays a central role in people’s lives and is intrinsically tied to many other aspects of people’s wider well-being. This was underscored during the COVID-19 pandemic, when direct health impacts and loss of lives combined with social isolation, loss of work and financial insecurity all contributed to a significant worsening of people’s mental health. Data from 15 OECD countries suggest that by late 2020, over one-quarter of people experienced symptoms of depression or anxiety. Already, well before the pandemic hit, it was estimated that half of the population will experience a mental health condition at least once in their lifetime and the economic costs of mental ill-health amounted to more than 4% of GDP annually. Good mental health, on the other hand, can boost people’s resilience to stress, help them realise their goals and actively contribute to their communities. Positive mental health, or having high levels of emotional and psychological well-being, is also increasingly being recognised as policy target in its own right by health and other government agencies across the OECD.
It is essential for governments interested in improving mental health to monitor outcomes for both ill-health and positive mental health at the broader population level. Statistics that only consider people diagnosed or treated by health care professionals are strongly affected by how accessible and developed a country’s health care system is, and identifying at-risk groups early on requires tracking outcomes well before a person engages with health care services. Moreover, good mental health is a foundational asset for the population, and as such, is valuable to track in its own right. Successful mental health promotion strategies also require understanding of how broader risk and resilience factors, such as people’s material conditions, quality of life and social relationships (and inequalities in these), impact their mental health. Data on these topics are typically collected in (social) population survey statistics that can be expanded to include mental health outcomes, to support this greater understanding and provide a better evidence base for policy.
Internationally, data on population-wide mental health outcomes are increasingly available but remain infrequently collected and poorly harmonised across countries. Several of the population mental health statistics the OECD is regularly publishing in its long-standing effort to promote a society-wide response to improving mental health are only available on a regular basis for a subset of OECD countries, are more than five years old at the time of publication for several countries, and in some cases stem from non-official data sources.
This report aims to support national statistical offices and other data producers in collecting high-quality measures of population mental health outcomes in a more frequent, consistent and internationally harmonised manner. The OECD took stock of what member countries are already doing in this area with a questionnaire that was shared with the OECD Committee on Statistics and Statistical Policy in February 2022. Almost all national statistical offices, and in many cases also health agencies, reported back. The report documents existing measurement practice to identify where countries are converging when it comes to gathering population mental health outcomes, and where gaps remain. In addition, available measurement tools are assessed to provide recommendations for priority measures official data producers can adopt in household, health and social surveys.
Collecting data on both mental ill-health and positive mental health at the population level would yield a more complete picture of mental health. Integrating relevant questions in population surveys that include information on other aspects of people’s lives would help better understand the drivers and policy levers associated with improving mental health outcomes. This can provide new avenues for proactive rather than reactive policy design, and mental health strategies that both reduce ill-health and promote good emotional and psychological well-being.
The pandemic has spurred new efforts in mental health data collection, and it will be important to keep up the momentum. Since March 2020, 7 in 10 OECD countries added mental health modules to existing surveys or launched new mental health surveys, many of them administered multiple times per year, or even more frequently. It is unclear whether these will continue in the future. A return to business as usual prior to the pandemic would mean that half of OECD countries only collect mental health data every four to ten years.
Some aspects of mental health are more frequently captured than others, and there is scope for better cross-country harmonisation of measures. This is in particular reflected by lack of harmonisation when it comes to measuring symptoms of anxiety, affect and eudaimonia (i.e. a sense of meaning and purpose in life), and very uneven use of tools that assess specific mental health conditions beyond anxiety and depressive disorders.
The report suggests adding four specific tools in relevant population surveys to build a small set of more internationally harmonised population mental health indicators. These recommendations have been formed based on a comparative assessment of their statistical quality, their response burden and cost, and existing data collection practices. They do not imply the phasing out of other tools that OECD countries are already using to capture population mental health outcomes.
Mental ill-health – priority recommendation: The Patient Health Questionnaire-4 (PHQ-4) could be included in more frequent surveys, alongside the regular collection of the PHQ-8 or PHQ-9 in health surveys. It covers symptoms of both depression and anxiety, and does so with only four questions.
Positive mental health – recommendation: Based on trends in country measurement practice, either the WHO-5 or SWEMWBS could be used to measure affective and eudaimonic aspects of positive mental health in a comparative way. The topic of measuring affect and eudaimonia specifically will continue to be explored in future OECD work on subjective well-being.
General mental health status – recommendation: Similar to commonly used questions that ask respondents to rate their physical health, a single question about a respondent’s general mental health status could be included in a range of surveys across a country’s broader data infrastructure system. Over half of countries include such questions already, though question wording varies widely. The following framing has been adopted by at least three OECD countries: “In general, how is your mental health? Excellent / Very good / Good / Fair / Poor.”