Global Mental Health Crisis: 1.2 Billion Affected, Study Finds

The most widespread and threatening illnesses aren’t ebola or the hantavirus, but mental health disorders, according to a new study published in the Lancet medical journal. With more than a billion people affected, should you be worried?

Published on Thursday, the study found that nearly 1.2 billion people worldwide had a mental disorder in 2023, an increase of 95% since 1990. Out of 12 disorders studied, the researchers found the sharpest increases in anxiety disorders and major depressive disorders, which rose by 158% and 131%, respectively. These two conditions are now the world’s most prevalent mental illnesses.

What mental disorders were studied?

The study’s authors recorded the prevalence of the 12 most common mental disorders, which they found were:

Anxiety disorders

Major depressive disorder

Dysthymia (a chronic but mild form of depression)

Bipolar disorder

Schizophrenia

Autism spectrum disorders

Conduct disorder

Attention-deficit hyperactivity disorder (ADHD)

Anorexia nervosa

Bulimia nervosa

Idiopathic developmental intellectual disability (IDID, or intellectual disabilities of unknown cause)

A residual category of other mental disorders

Who is at risk?

With the exception of ADHD and IDID, which dropped by 1.8% and 16.4%, respectively, all of these disorders have increased in prevalence. The increase was not distributed equally, however. Most of the 12 conditions are more common among women, with depression, anxiety, bipolar disorder, anorexia, and bulimia all more likely to affect females. ADHD, autism, and conduct disorder – which manifests as aggression and disobedience – are all more prevalent in males.

Mental disorders are most common in people aged 15 to 19, the study found, marking the first time that this demographic bears the highest mental health burden.

Research was carried out in 204 countries and territories, and while the study noted increases across the world, Western countries are the most affected. Measuring ‘life years’ of mental illness, the researchers found a mental illness rate of 3,555 per 100,000 in the Netherlands, and 1,302 in Vietnam, for example.

Middle-developed countries as a whole had average mental illness rates of around 1,853 per 100,000, while highly developed countries had rates of around 2,184 per 100,000.

Why are more people mentally ill?

“There are many factors at play here, and it is difficult to tease them all apart,” lead researcher Dr. Damian Santomauro told CNN. However, Santomauro’s colleague, Dr. Robert Trestman, highlighted one key factor: “The stigma of mental illness has been substantially reduced, [and] people are much more comfortable coming forward, as opposed to suffering in silence.”

While Trestman attributes the rise to loosening stigmas, others point to overdiagnosis of mental disorders.

Overdiagnosis

Between 2013 and 2025, the number of mental health cases handled by England’s National Health Service more than doubled, from just under four million in 2013 to nine million in 2025. With autism and ADHD rates driving the increase, Health Secretary Wes Streeting claimed that “there’s an overdiagnosis” of these conditions, and ordered a government review into the matter last December.

At the time, the BBC asked 750 British doctors whether they agreed with Streeting’s comments. 442 said they did, with only 81 saying that mental health problems were being under-diagnosed.

“As a society we seem to have forgotten that life can be tough – a broken heart or grief is painful and normal, and we have to learn to cope,” one doctor told the BBC.

In a 2022 study, Australian researchers identified “concept creep” as a key driver of overdiagnosis. They argued that by broadening the definition of some disorders, doctors and psychiatrists have pathologized once-normal behaviors: for example, a boy refusing to sit still in school is more likely to be diagnosed with ADHD nowadays than in 1990.

Big pharma profiting

One of the doctors who spoke to the BBC said that they find themselves “regularly reaching for antidepressants, which I know may only help short term and won’t help prevent recurrence.” As of 2022, roughly 14.7% of the population in England has a prescription for antidepressants, and the number of 5-12-year-olds on these drugs has risen by 41% between 2015 and 2021, according to the pharmaceutical journal. Antidepressant use has soared by 147% in the EU between 2000 and 2020, and by 65% in the US during the same time.

All of these numbers translate into massive profits for the pharmaceutical industry. According to Fortune, the global antidepressant market is expected to grow to $18.3 billion in 2027. Big Pharma is working to drive these numbers up through diagnosis, Fortune notes, highlighting how “for-profit organizations and governments are working to create awareness among the general population about various mental conditions,” which “assists market growth potential.”

Beginning in the 1980s, pharmaceutical companies lobbied the American Psychiatric Association to reclassify depression from an episodic phenomenon to a long-term “disorder” requiring medication. Drugmakers then funded studies to prove that their products – in this case SSRI (Selective Serotonin Reuptake Inhibitor) drugs – worked, and doctors were incentivized to prescribe them.

Modern research has found that many early SSRI trials were rigged by the industry, and multiple companies – including GlaxoSmithKline, Forest Laboratories, and Takeda – have been sued for offering doctors kickbacks in exchange for prescribing more antidepressants. In a 2012 settlement, GlaxoSmithKline paid $3 billion in damages for unlawfully promoting Paxil and Wellbutrin, including by offering meals and hotel stays to doctors who prescribed the two medications.

With the exception of conduct disorder, every condition mentioned in the Lancet study is treated with prescription drugs, meaning the pharmaceutical industry has a baked-in incentive to promote their diagnosis.

Modernity is bad for our health

While overdiagnosis and the greed of the pharmaceutical industry go a long way toward explaining the rising prevalence of mental illness, some scientists believe that the modern world itself is making us sick. As psychiatrist Dr. Alex Curmi explained in The Guardian last year, humans evolved to live in close-knit bands of hunter-gatherers, performing hands-on work in “communities rich with tradition, ritual and spiritual meaning,” rather than living atomized and sedentary lives in cities, subsisting on chemical-laden food, and bombarded by news cycles of misery and violence.

“Modern populations are increasingly overfed, malnourished, sedentary, sunlight-deficient, sleep-deprived, and socially-isolated,” read a 2012 study titled ‘Depression as a disease of modernity’. The study also noted “A positive correlation between a country’s GDP per capita…and lifetime risk of a mood disorder.”

The Lancet study found soaring rates of mental illness after the Covid-19 pandemic, a time of lockdowns, isolation, joblessness and stress for hundreds of millions of people worldwide.

Certain elements of modern life have had a clear and well-documented negative effect on our mental health. After more than 143 peer-reviewed studies, there is a growing consensus that social media use is linked with depression, anxiety, and eating disorders like anorexia and bulimia nervosa, particularly among teenagers.

It is now the official opinion of the US Surgeon General that adolescents – the group which saw the largest rise in mental disorders in the Lancet study – who spend more than three hours per day on social media double their risk of developing anxiety and depression. Just under half of US teens feel that social media use has a “mostly negative” impact on their mental health, a Pew Research survey found last year.

Should you worry?

The short answer here is ‘it depends’. While the risk of mental disorders seems to increase along with a country’s GDP, it’s worth bearing in mind that the richest and most developed countries are also the largest markets for the pharmaceutical industry, making it more likely that their citizens will be overdiagnosed and overmedicated.

More broadly, some solutions are obvious: limiting screen time and social media use, eating well and exercising, building strong relationships, meditation and prayer are all recognized by both science and common sense as conducive to good mental health.