New Delhi: Mental disorders are now officially the world’s leading cause of disability, overtaking conditions such as cardiovascular disease, cancer and
musculoskeletal illnesses, according to a major new study published in The Lancet. In 2023, nearly 1.2 billion people worldwide were living with a mental health condition almost double the figure recorded in 1990 and this has pushed mental illness into the top spot when it comes to years lived with disability. The analysis, part of the Global Burden of Disease 2023 study, shows that mental health problems now account for more than 17 per cent of all disability across the world, highlighting how deeply they affect education, employment, relationships and day‑to‑day life.
What makes this situation even more worrying is that teenagers, especially those aged 15–19, are bearing the heaviest burden. Girls and young women are also disproportionately affected, with anxiety and depression striking them at higher rates than boys and men.
What does the new Lancet study say?
A large global analysis published in The Lancet in 2026, using data from the Global Burden of Disease 2023 study, shows that mental disorders have now become the leading driver of disability worldwide. The study was led by researchers from the University of Queensland, Queensland Centre for Mental Health Research, and the University of Washington’s Institute for Health Metrics and Evaluation (IHME). It reveals that mental health conditions now rank ahead of cardiovascular disease, cancer and musculoskeletal problems when measured in “years lived with disability” (YLDs), which is the total number of years people spend living with ill‑health or impairment.
In 2023, mental disorders were responsible for about 171 million disability‑adjusted life years (DALYs) globally, and accounted for more than 17 per cent of all years lived with disability. This means that, for many people, a mental health problem is not just a short phase of sadness or worry but a long‑term condition that seriously affects how they function at home, school, college or work.
How many people are affected by mental disorders
The Lancet study estimates that around 1.2 billion people worldwide were living with a mental disorder in 2023, which is roughly one in seven people on the planet. This number has almost doubled compared with 1990 levels, reflecting both population growth and a genuine rise in the prevalence and severity of mental health problems. The biggest contributors to this increase are anxiety disorders and major depressive disorder, which together form the core of what some experts call the “quiet epidemic” of poor mental health.
Globally, women are more affected than men: about 620 million women live with a mental disorder, compared with 552 million men, and women account for more disability‑adjusted life years lost to mental illness. This gender gap is linked to biological, social and economic pressures, including greater exposure to stress, discrimination, caregiving responsibilities and unequal access to resources and support.
Why are teenagers most affected
According to the Lancet analysis, the highest mental health burden is now seen among 15–19‑year‑olds, making adolescence the peak period for mental disorder–related disability. This age group is going through rapid brain development, hormonal changes, academic pressure, identity formation and social media exposure, all of which can magnify stress and make them more vulnerable to anxiety, depression and other conditions. Earlier studies show that roughly 13–14% of adolescents aged 15–19 already have at least one mental disorder, and this proportion is rising steadily.
In teenagers, the leading mental health problems are anxiety disorders and major depressive disorder, while neurodevelopmental and behavioural conditions such as attention‑deficit/hyperactivity disorder (ADHD), autism spectrum disorder and conduct disorder are also common, especially in younger adolescents. Boys tend to have higher rates of ADHD, conduct disorder and autism, while girls show higher rates of anxiety and depression, partly because of differences in brain development, hormone patterns and social expectations.
Which mental disorders cause the most disability?
The Lancet‑linked Global Burden of Disease work shows that several specific disorders are responsible for the bulk of mental‑health‑related disability. The main ones are:
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Major depressive disorder (clinical depression)
Depression is the largest single contributor to mental‑health‑related disability, affecting millions of people across all ages but especially young adults and women. People with depression often struggle with low energy, poor sleep, difficulty concentrating and loss of interest in activities, which can severely disrupt school, work and relationships. -
Anxiety disorders
These include generalised anxiety disorder, social anxiety, panic disorder and phobias, and they now rank among the top causes of disability worldwide. Anxiety can make it hard to go to school, attend interviews, speak in public or even meet friends, leading to isolation and missed opportunities. -
Neurodevelopmental and behavioural disorders
ADHD, autism spectrum disorder, conduct disorder and intellectual disability contribute significantly to disability in children and adolescents. These conditions often start early in life and can affect learning, social skills and behaviour, especially if they are not spotted and supported in time.
Why has the burden of mental disorders nearly doubled since 1990
Several interconnected factors explain why mental‑health‑related disability has surged by about 95–100% since 1990. Population growth and longer life spans mean there are simply more people living with long‑term conditions, including mental illnesses. At the same time, social and economic changes—such as rising academic pressure, unemployment, cost‑of‑living stress, urbanisation and weaker community ties—have increased chronic stress and loneliness, both of which are powerful triggers for anxiety and depression.
Technology and social media are another important piece of the puzzle. Constant comparison, cyberbullying, sleep disruption from late‑night screen use and the pressure to be “always on” are especially harmful for teenagers whose brains are still developing. The Covid‑19 pandemic also played a role, with studies showing that isolation, school closures, grief and uncertainty led to a measurable spike in mental‑health problems in young people and adults.
The new Lancet study is a stark reminder that mental disorders are no longer a “side issue” in global health—they are now the leading cause of disability worldwide, with teenagers and young women hit hardest.
