Our World
in Data
Oxford Martin School logoUniversity of Oxford logoGlobal Change Data Lab logo
HomeMental Health

When do people experience mental health conditions for the first time?

Knowing when people are most at risk allows us to offer support when it might make the biggest difference.

By Hannah Ritchie
October 19, 2026Cite this article

Mental health conditions can begin at almost any age. For many people, they develop in the early stages of life.

Around a third of people who will ever experience a mental health disorder do so by the age of 14.1 Two-thirds do by the age of 25.

But this varies a lot by condition. Some are much more common in childhood or adolescence, while others are more evenly distributed across adulthood. Knowing the age at which people might be particularly vulnerable to the onset of a mental health condition is important. It helps societies offer support — whether that’s an assessment of risk factors, screening, or preventive interventions — at the right time to make a difference.

The chart below shows how this age distribution looks for nine different mental health disorders. Each curve shows, among people who will ever develop that condition, the share who first do so at any given age.

The data behind this comes from a large meta-analysis of 192 studies by Marco Solmi and colleagues.1

Around a third of people who will ever experience a mental health disorder do so by the age of 14.

I’ve sorted these conditions into three groups.

First, those that commonly develop at any point in someone’s life. This includes generalized anxiety disorder, depression, and bipolar disorder (the latter two are often referred to as mood disorders).

Second, those that tend to develop earlier in life, with a very strong age peak around early adolescence. Social anxiety tends to first develop in childhood, and almost 80% of those who will experience it at some point in their lives do so before the age of 18. Eating disorders tend to begin during someone’s teenage years, with a peak age of 16 and a median age of 18.2

And third, those that tend to peak around age 20 but will often develop for the first time throughout adulthood. This includes substance use (alcohol and cannabis) disorders and schizophrenia, which commonly develop in someone’s twenties.

Density plots of age of onset for a range of mental health disorders where the visualization compares when different conditions typically first appear across the lifespan, grouped into disorders that often develop at any point in life, those most likely in childhood or adolescence, and those most likely in early adulthood. Each curve shows the concentration of first onset at each age (the area under each curve is the same, so taller peaks indicate a more concentrated age of onset rather than greater prevalence), illustrating that social anxiety, obsessive-compulsive, and eating disorders tend to peak in adolescence, many substance use disorders and schizophrenia peak in early adulthood, while depression, bipolar disorder and generalized anxiety are more spread across ages. Source: Solmi et al. (2022) meta-analysis via OurWorldInData; License: CC BY (author Hannah Ritchie).
Additional informationSome notes on the data used in this visualization

The chart above uses smoothed curves from the meta-analysis published by Marco Solmi and colleagues in Molecular Psychiatry.

Here are a few things to keep in mind when interpreting this data.

First, the definition of onset age varied among the underlying studies in the meta-analysis. In some, it meant the age at which someone first experienced symptoms. In others, the age of diagnosis or first hospitalization. Differences in this definition can, of course, affect these results; someone may experience symptoms long before they receive a diagnosis. This could shift the median age of onset significantly. The authors did test the sensitivity of their results to different definitions and found, for example, that shifting from symptoms to diagnosis for depression changed the median age from 26 to 31 years.

Second, these curves do not tell us anything about how prevalent these conditions are across the entire population. They are scaled by the proportion of people who will ever develop a given condition. The depression curve, for example, is far lower than the schizophrenia curve, even though depression is much more common in the general population.

Third, this data only tells us about the age of onset. It does not tell us about the age distribution of people experiencing the condition at any given time. Many people will have recurring episodes — or very long periods — with a given mental health disorder, which isn’t reflected in the chart.

Finally, these curves are limited by the number of high-quality studies of different conditions. In particular, geographical diversity is limited, with most studies coming from high-income countries in North America, Europe, or Australia.

Acknowledgments

Many thanks to Edouard Mathieu and Max Roser for feedback and comments on this article and its visualization.

Continue reading on Our World in Data

Endnotes

  1. Solmi, M., Radua, J., Olivola, M., Croce, E., Soardo, L., Salazar de Pablo, G., ... & Fusar-Poli, P. (2022). Age at onset of mental disorders worldwide: large-scale meta-analysis of 192 epidemiological studies. Molecular Psychiatry.

  2. Eating disorders, here, include anorexia nervosa, bulimia nervosa, and binge-eating disorder.

Cite this work

Our articles and data visualizations rely on work from many different people and organizations. When citing this article, please also cite the underlying data sources. This article can be cited as:

Hannah Ritchie (2026) - “When do people experience mental health conditions for the first time?” Published online at OurWorldinData.org. Retrieved from: 'https://archive.ourworldindata.org/20261019-000106/when-do-people-experience-mental-health-conditions-for-the-first-time.html' [Online Resource] (archived on October 19, 2026).

BibTeX citation

@article{owid-when-do-people-experience-mental-health-conditions-for-the-first-time,
    author = {Hannah Ritchie},
    title = {When do people experience mental health conditions for the first time?},
    journal = {Our World in Data},
    year = {2026},
    note = {https://archive.ourworldindata.org/20261019-000106/when-do-people-experience-mental-health-conditions-for-the-first-time.html}
}

Past versions

We are a live site and we keep our work maintained. So our articles are often changed, including the data. You can browse previous versions of this work here.

Our World in Data logo

Reuse this work freely

All visualizations, data, and articles produced by Our World in Data are completely open access under the Creative Commons BY license. You have the permission to use, distribute, and reproduce these in any medium, provided the source and authors are credited.

The data produced by third parties and made available by Our World in Data is subject to the license terms from the original third-party authors. We will always indicate the original source of the data in our documentation, so you should always check the license of any such third-party data before use and redistribution.

All of our charts can be embedded in any site.