Globally, around 300 million people are affected by depression at any moment (WHO, 2017). With depression being projected as the single leading cause of disease burden in high-income countries by 2030, intervening and preventing depression is crucial (Mathers & Loncar, 2006).

However, the prevalence of depression shows no sign of decreasing. Authors of a recent paper raise the question, what is needed to reduce the prevalence of depression? (Ormel et al., 2019).

Preventing depression: can we do it globally?

Ormel and colleagues (2019) begin their review by summarising the evidence that the prevalence of depression has not dropped; in fact, it might have increased. They discuss key issues with preventative strategies, outlining the limitations of current research into preventing depression. They highlight the importance of several pre-requisites they deem as essential for targeting modifiable risk factors.

Preventive interventions to date are described as having “unfulfilled potential”. They present evidence of efficacy, but the effect sizes are small for targeted interventions, and even smaller for universal ones.

Then we come across a further problem: for preventive strategies to have large effects, we need “strong and modifiable” determinants. This is straightforward in the analogy provided in the article: smoking and lung cancer. The authors identify broad-ranging risk factors, but even the risk factors cited as the strongest (i.e. gender, genetics or negative affect), still have far lower odds ratios than that of smoking and lung cancer (Pesch et al., 2011).

A further complexity is that many of the risk factors for depression (such as genetics or social inequality) appear difficult to modify. The few that are cited as modifiable include personality traits, parenting, and thinking styles, although these risk factors are arguably still far more complex and harder to change than smoking.

Recommendations

The authors particularly focus on implementing interventions at the level of personality traits (particularly neuroticism and conscientiousness) and life skills, and also argue how this may indirectly affect environmental risk factors too. The following recommendations for preventing depression are provided:

1. Socially embedded, structurally funded, and backed up by the law: particular emphasis is placed on embedding interventions at a political and social-psychological level to ensure long-term sustainability.
2. Prevention starts in early life and targets both parent and child to interrupt maladaptive continuity: the authors present a body of evidence depicting the importance of targeting personality traits/life skills in early life, and to provide interventions for parents and children simultaneously.
3. Target major upstream determinants: poor parenting and children’s maladaptive personality and life skills: this emphasises the importance of targeting poor parenting and children’s maladaptive personality traits and life skills simultaneously. As these factors influence each other, addressing both issues will result in larger amounts of change.
4. Emphasis on universal prevention: this highlights the importance of normalising and destigmatising mental ill-health. For this to be achieved, prevention programmes must be universal and a part of everyday life.

Conclusions

Ormel et al. highlight that while preventing depression is thought of as important by many, prevention research and strategies are currently limited. They argue that:

the only way to substantially reduce initial and recurrent episodes of depression is large-scale, socially embedded, structurally funded, and universal prevention supplemented with remedial selective/indicated prevention for those who need more.

The authors acknowledge that their recommendations may be difficult to achieve, but believe the proposal of improving individual resilience and reducing vulnerability to depression are key areas to consider.

Finally, they point towards the importance of mental health professionals continuing to encourage prevention strategies to be socially embedded within universal institutions, such as schools.

Strengths and limitations

A major strength of this paper is that it tackles the ambitious and crucial issue of prevention in common mental illness. An accusation we’ve often heard levelled at mental health services is that they respond to crises, rather than avoiding them. Therefore, research focusing on prevention recommendations is important. The review is wide-ranging, balanced, and considered.

The paper discusses proposals for preventing depression in light of the high prevalence of depression in the population. However, it may be more beneficial to consider depression within the context of common mental disorders (CMDs), given evidence of a high co-morbidity between depression and anxiety and that CMDs have a higher prevalence than depression alone (McManus et al., 2016). Thus, it may be appropriate to focus more transdiagnostically as opposed to targeting specific determinants of depression in isolation.

The authors propose the importance of prevention strategies being consolidated by law and highlight how this may facilitate the other proposed conditions for prevention. However, political change often requires strong evidence of an association between a risk factor and an outcome. For this to happen, more research investigating causal factors of depression is required, prior to political change.

The role of building resilience is an area that seems well placed within a public health context in preventing depression, yet is only briefly mentioned in the paper.

Implications

Although the recommendations are logical, it appears that the authors have jumped ahead in their conclusions without specifying what actually needs to be targeted.

The authors themselves acknowledge that depression is a complex condition, with many combinations of risk factors, but it would be impossible to implement the model to target all of these universally.

It appears that the model better lends itself for targeting one or two isolated risk factors, but this is a more reductionist approach. However, given the extremely high prevalence of depression, implementing a universal prevention strategy to reduce a small number of risk factors is still likely to help thousands of people and be cost-effective for the NHS.

Links

Primary paper

Ormel, J., Cuijpers, P., Jorm, A., & Schoevers, R. (2019) What is needed to eradicate the depression epidemic, and why. Mental Health & Prevention, 17, 200177. https://doi.org/10.1016/j.mhp.2019.200177

Other references

Mathers, C.d., & Loncar, D. (2006).  Projections of global mortality and burden of disease from 2002 to 2030. Plos Med, 3(11), e442.

McManus, S., Bebbington, P., Jenkins, R., & Brugha, T. (2016). Mental health and wellbeing in England: Adult Psychiatric Morbidity Survey 2014. A survey carried out for NHS Digital by NatCen Social Research and the Department of Health Sciences, University of Leicester.

Ormel, J., Cuijpers, P., Jorm, A., & Schoevers, R.A. (2020). What is needed to eradicat the depression epidemic, and why. Mental health & Prevention, 17.

Pesch, B., Kendzia, B., Gustavsson, P., Jöckel, K. H., Johnen, G., Pohlabeln, H., … & Wichmann, H. E. (2012). Cigarette smoking and lung cancer—relative risk estimates for the major histological types from a pooled analysis of case–control studies. International journal of cancer, 131(5), 1210-1219.

World Health Organization. (2017). Depression and other common mental disorders: global health estimates (No. WHO/MSD/MER/2017.2). World Health Organization.

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