Rediscovering the mental health of populations

The principles of prevention espoused by G. Rose ¹ have underpinned many modern successes in health care. In areas such as cardiometabolic diseases, injuries and violence, and substance abuse, shifting the community distribution of risk factors has become the primary strategy. The ensuing reductions in disease burden have been striking.

Psychiatry remains an outlier. Over decades, the quality of clinical care has been improved, greater funding has been attracted, more and better trained mental health professionals have been grown, and the governance of mental health care has been upgraded ² . However, the emphasis in recent initiatives in high‐income countries has been overwhelmingly a further extension of treatment: early clinical intervention has been the dominant initiative taken up in government investments into the mental health of young people ³ .

Yet, this continuing expansion of government expenditure, prescribing of antidepressants and availability of psychological services has still not been accompanied by reductions in the prevalence of common mental disorders ³ . While it remains possible that this in part reflects a continuing failure to scale minimally‐sufficient treatments, the evidence from other fields of medicine suggests that a more likely explanation is the lack of scalable risk‐focused prevention strategies.

This failure to embrace population‐based approaches to prevention in psychiatry is understandable. Most clinicians find the endorsement of population perspectives difficult. For them, the individual is the unit of study ¹ . For psychiatry, the opacity of pathophysiological processes has supported the tendency to focus on interventions directed at the individual. Recent excitement about progress in genetics and neuroscience has reinforced this tendency, with both major research funding agencies and the pharmaceutical industry emphasizing the individual over the social context.

In this scenario, the paper by Fusar‐Poli et al in this issue of the journal ⁴ raises questions around the optimal strategies for prevention in psychiatry. The overwhelming emphasis to date across common mental disorders, psychosis and bipolar disorder has been on individuals at high risk by virtue of early clinical symptoms or genetic predisposition. These selective and indicated approaches to prevention have targeted subjects at the tail of the distribution, with an aim of reducing the likelihood of transition to clinical caseness. However, this emphasis on individuals has been accompanied by a failure to address structural and social determinants.

E. Durkheim’s work, well over a century ago, drew the conclusion that suicide rates are stable and distinctive characteristics of populations. He viewed suicide as a collective phenomenon in which personal factors are less important than the social context. Similarly, strategies focused on the social, economic and regulatory context that bring a reduction in average alcohol consumption have been far more successful in reducing levels of alcohol use disorders than individually targeted interventions ⁵ . This principle that actions to reduce modest risks in a large group will generate greater benefits than targeting conspicuous risks in a small number should guide the prevention of mental disorders.

One challenge is that most risks for mental disorders lie outside the direct influence of the health sector. For young people, social determinants of mental health derive from inequitable gender norms, shifts in family structure and function, culture and religion, economic development and its consequences, digital technology, urbanization and planetary change. These social and structural determinants shape peer, family and community relationships, accessibility of service systems, the likelihood of experiencing major external events, as well as risks related to lifestyle and individual behaviour. For mental disorders, as for the physiological processes underpinning physical health, there are also sensitive periods in which risks are more likely to become embedded and when prevention will be more effective.

The COVID‐19 pandemic illustrates the influence of social and structural factors on the mental health of all age groups, but particularly the young. It also illustrates areas where psychiatry should be acting. The effects of lifestyle risk factors for mental disorders, including physical inactivity, screen time, irregular sleep and poor diets, have been enhanced. Even more profound have been the shifts in relationships, with disruption to friendships and peer interactions, heightened worries about and sometimes conflict with family members, confinement to home and loss of the social milieu of schools, including extracurricular activities.

In taking prevention in psychiatry forward, there are further lessons to be drawn from other areas of medicine ¹ . Epidemiology remains the underpinning discipline of public health, and, for psychiatry, epidemiology should adopt both life‐course and population perspectives. However, psychiatric epidemiology remains in a parlous state, particularly for children and young people. Global coverage for even basic estimates of prevalence lies under seven percent, with rates in low‐ and middle‐income countries substantially lower, and 124 countries having absolutely no data ⁶ . Coverage of risk factors is even weaker.

As noted by Fusar‐Poli et al, a life‐course perspective on mental health is essential ⁴ . Yet, a life‐course perspective would ideally extend across generations, given that familial clustering is the clearest of all risk factors. Beyond genetics, there are malleable intergenerational risk factors for mental disorders, ranging from the biological (e.g., epigenetic) through to the structural (e.g., inequitable gender norms), including those risks that become embedded prior to conception ⁷ . Longer‐term perspectives derived from prospective life‐course studies have the potential to guide prevention research and policy, particularly when combined with powerful new analytic tools for causal inference.

Recent intervention trials provide grounds for optimism. Schools will be one important context for prevention. Children and young people spend close to half their waking hours in school and education. Policy‐makers increasingly understand that poor student mental health affects learning and academic achievement. There are now examples from both high‐ and low‐resource settings that interventions promoting a positive school social climate and reducing bullying can substantially reduce symptoms of common mental disorder ⁸ . Other promising platforms include those based in local communities (e.g., girls clubs) and the new social environments created by digital media.

Interventions well beyond those traditionally regarded as the focus for prevention of mental disorders will also be important. Cash transfers have been widely adopted by governments in other areas of health and social policy, and seem to bring reductions in symptoms of mental disorder and promotion of well‐being in low‐resource settings where psychological interventions based on cognitive behaviour therapy have little or no effect ⁹ . Such findings suggest the value of inclusion of mental health into trials of non‐mental health interventions.

The dramatic deterioration in community mental health during the COVID‐19 pandemic heightens the imperative for psychiatry to shift beyond its comfort zone of the individual patient, and engage with the social, structural and political determinants of mental health.