More than 1 billion people now living with a mental disorder

By Stephen Beech

Mental disorders have nearly doubled since 1990 — now affecting more than one billion people worldwide, according to new research.

Mental health is now the leading cause of years lived with disability globally, accounting for more than one in six of all disability cases globally, suggests the study.

And the highest mental disorder burden is seen among young adults aged 15 to 19 and women of all ages — driven largely by anxiety and depressive disorders, say scientists.

Some of the highest levels of mental disorders are in Western Europe, according to the findings published in The Lancet.

Researchers found that nearly 1.2 billion people worldwide are living with a mental disorder, nearly double the number recorded in 1990.

The study, led by researchers at the Institute for Health Metrics and Evaluation (IHME) in Seattle, working with colleagues at the University of Queensland, Australia, identified that mental disorders "disproportionately impact" people aged 15 to 19 and women.

The research team examined the prevalence and burden of mental disorders across both sexes, 25 age groups, 21 regions, and 204 countries and territories from 1990 to 2023, making it the most comprehensive analysis of mental disorder burden to date.

The study assessed 12 mental disorders, with anxiety disorders and major depressive disorder (MDD) ranking 11th and 15th, respectively, in burden among 304 diseases and injuries worldwide.

Mental disorders are now the leading driver of disability worldwide.

In 2023, mental disorders accounted for 171 million disability-adjusted life years (DALYs) globally, placing the conditions as the fifth-leading cause of total disease burden.

DALYs are a measure of overall health loss, combining years lived with disability and years of life lost due to premature death.

Mental disorders accounted for more than 17% of all years lived with disability worldwide.

Recent increases have been driven largely by anxiety disorders and major depressive disorder, according to the research team.

Since 2019, the age-standardized prevalence of major depressive disorder has risen by around 24%, while anxiety disorders have increased by more than 47%, with both conditions peaking in the years following the COVID-19 pandemic.

Study first author Damian Santomauro, of the Queensland Centre for Mental Health Research, said: "These rising trends may reflect both the lingering effects of pandemic-related stress and longer-term structural drivers such as poverty, insecurity, abuse, violence, and declining social connectedness.

"Addressing this growing challenge will require sustained investment in mental health systems, expanded access to care, and coordinated global action to better support populations most at risk."

He says mental disorders affect people across all stages of life, but the types of conditions and their impact vary by age.

In early childhood, conditions such as autism spectrum disorder, attention-deficit/hyperactivity disorder (ADHD), conduct disorder, and idiopathic developmental intellectual disability are most prevalent, with boys affected at higher rates than girls.

But as children grow into adolescence, anxiety and MDD are the leading contributors to mental disorder burden.

Study co-author Alize Ferrari, also of the Queensland Centre for Mental Health Research, added: "Our findings show that mental disorder burden peaks among 15- to 19-year-olds, which is a critical developmental period that can shape trajectories for education, employment, and relationships."

The study showed that, in 2023, 620 million women of all ages were living with a mental disorder compared to 552 million men of all ages globally.

Women accounted for 92.6 million DALYs, compared to 78.6 million among men, indicating a higher overall burden.

The research team say the differences are likely shaped by a complex mix of factors, including greater exposure to domestic violence and sexual abuse and increased caregiving responsibilities.

The findings also showed that mental disorders burden increased in every region of the world between 1990 and 2023, though the scale and pattern of that burden differ substantially across regions and levels of development.

High-income regions such as Western Europe and Australasia recorded some of the highest burden rates globally, particularly in countries including the Netherlands, Portugal, and Australia.

Large increases in mental disorder burden rates were also observed in Western sub-Saharan Africa and parts of South Asia.

But across 204 countries and territories, only a small number of high-income settings — including Australia, Canada, and the Netherlands — have treatment coverage exceeding 30%, highlighting major global gaps in care.