Nearly 1.2 billion people globally were living with mental disorders in 2023, marking a 95.5 per cent increase since 1990, according to a new study published in The Lancet on Thursday.
The research found that anxiety and depression recorded the sharpest rise and remained the most common mental health conditions worldwide in 2023.
Personality disorders not linked with substance abuse or other mental illnesses ranked third among the most prevalent disorders.
The study examined trends across 12 mental disorders in 204 countries and territories, analysing differences based on age, sex, location and socio-demographic factors.
The authors warned that the findings suggest “that we are entering an even more concerning phase of worsening mental disorder burden globally.”
Dr. Damian Santomauro, the study’s lead author and associate professor at the School of Public Health at the University of Queensland, said he was surprised by the scale of the increase.“was honestly shocked at the magnitude,” he said via email.
“There are many factors at play here, and it is difficult to tease them all apart,” Santomauro added. “Addressing these risk factors requires global collective leadership.”
The disorders covered in the study included bipolar disorder, schizophrenia, autism spectrum disorder, attention deficit hyperactivity disorder, anorexia, bulimia, dysthymia, conduct disorder and developmental intellectual disability from unknown causes.
Researchers reported increases across all 12 disorders. Anxiety cases rose by 158 per cent, while depression climbed by 131 per cent compared with 1990 figures.
Although anorexia, bulimia and schizophrenia were among the least common conditions, the study estimated there were still around four million anorexia cases, 14 million bulimia cases and 26 million schizophrenia cases worldwide in 2023.
Most of the disorders were found to be more common in females. However, autism, conduct disorder, ADHD, personality disorders and unexplained intellectual disability were more prevalent among males.
The findings also highlighted the lingering impact of the Covid-19 pandemic on mental health.
Rates of anxiety, depression and several other conditions had already been increasing before the pandemic, but depression worsened during the crisis and remained above pre-pandemic levels afterward. Anxiety levels also peaked during the pandemic and stayed elevated through 2023.
Senior scientist in the Department of Mental Health at the Johns Hopkins Bloomberg School of Public Health, Paul Bolton, noted that underreporting remains a challenge in mental health research.
In the research, “issues like underreporting, a common problem with mental illness, are dealt with, but we really don’t know how accurate this is,” Bolton said via email.
However, he added that the estimates “are the best we have” and “as close to the real figures in the world as we are likely to get.”
The study drew its data from the 2023 Global Burden of Diseases, Injuries and Risk Factors Study (GBD), led by the Institute for Health Metrics and Evaluation at the University of Washington.
The project, launched in the early 1990s and primarily funded by the Gates Foundation since 2007, is regarded as one of the world’s most comprehensive health studies.
Researchers also observed a major shift in the age group most affected by mental disorders. Females and people between 15 and 39 years old were found to carry the greatest burden, with the highest rates now recorded among teenagers aged 15 to 19.
“we have historically always seen this peak in middle-age,” Santomauro said.
Experts said the younger age group is particularly vulnerable because adolescence is a critical period for brain development and the formation of social and intellectual skills.
Dr. Robert Trestman, chair of psychiatry and behavioural medicine at the Virginia Tech Carilion School of Medicine, said interrupted development at that stage can have lasting effects.
“The stigma of mental illness has been substantially reduced, people are much more comfortable coming forward, as opposed to suffering in silence,” Trestman said.
Specialists also pointed to improved diagnosis, population growth and longer life expectancy as factors contributing to the increase in reported cases.
At the same time, experts warned that worsening living conditions around the world are fuelling the mental health crisis. Economic hardship, trauma, political instability, armed conflict, discrimination, food insecurity, social isolation and inadequate healthcare were identified as some of the key drivers.
Santomauro noted that while young people were uniquely affected by the pandemic and other stressors, researchers still lack sufficient data explaining the sharp increase among youths.
“Unfortunately we don’t have much data on the causes of this increase among youth,” he said.
The authors stressed that mental health services have not expanded enough to meet the growing global demand.
“Concerningly, this increase in burden has not been accompanied by proportional expansion of mental health services,” the study authors wrote.
“Responding to the mental health needs of our global population, especially those most vulnerable, is an obligation, not a choice.”
Experts advised people struggling with mental health conditions to seek professional support, including therapy, medication and counselling where necessary.
They also recommended improving lifestyle habits such as diet, exercise, sleep, social connection, hobbies and maintaining a healthy work-life balance.
