The Netherlands has the highest rate of mental illness in the world, followed closely by Portugal and Australia. Based on 2023 data from the Institute for Health Metrics and Evaluation’s Global Burden of Disease study, the Netherlands has an age-standardized prevalence rate of roughly 22,893 per 100,000 people, meaning nearly 23% of the population lives with a diagnosable mental health condition. Globally, about 15% of the world’s population experienced a mental disorder in 2023, making these top-ranked countries significantly above average.
How the Top Countries Compare
The Netherlands leads with its 23% prevalence, and Portugal follows at about 22,116 per 100,000. Australia rounds out the top three. These are not countries in crisis or conflict. They are wealthy, stable nations with well-developed healthcare systems, which points to an important reality: higher reported rates of mental illness often reflect better detection, not necessarily worse mental health.
Countries with robust psychiatric infrastructure, widespread screening, lower stigma around mental health, and insurance systems that cover therapy are simply more likely to identify and count people with conditions like depression, anxiety, and ADHD. In nations where mental health services barely exist or where stigma keeps people from seeking help, many cases go undiagnosed and uncounted.
The United States: A Close Contender
The U.S. consistently ranks among the highest in the world for mental illness prevalence. In 2022, an estimated 59.3 million American adults were living with a mental illness, representing 23.1% of the adult population. That’s roughly one in five adults. The U.S. also carries one of the heaviest burdens when measured by years of healthy life lost to mental disorders, ranking at the top in the Americas for overall mental health disability.
For depression specifically, the picture shifts. Guyana leads the Americas with 941.5 disability-adjusted life years lost per 100,000 people, followed by Suriname at 894.4 and the U.S. at 800.0. These numbers capture not just how common depression is but how severely it affects people’s ability to function day to day.
Why Wealthy Countries Top the List
It may seem counterintuitive that some of the world’s richest nations report the highest mental illness rates. Several factors drive this pattern. First, these countries have the diagnostic tools and trained professionals to identify conditions that would go unnamed elsewhere. Second, lifestyle factors common in high-income societies play a role: social isolation, sedentary habits, work-related stress, substance use, and the pressures of economic inequality within otherwise wealthy nations.
Third, the definition of mental illness itself matters. Surveys in countries like the Netherlands, Australia, and the U.S. capture a broad spectrum, from mild anxiety and seasonal depression to severe conditions like schizophrenia. Many low-income countries only track the most visible, severe cases.
Conflict Zones Tell a Different Story
If every country had equal diagnostic capacity, the rankings would likely look very different. The World Health Organization estimates that in populations affected by armed conflict, the rate of mental health conditions is more than double that of the general population. About one in five people in conflict-affected areas lives with some form of mental disorder, and nearly one in ten has a moderate or severe condition.
Among displaced populations in Africa, the numbers are staggering. A meta-analysis published in Frontiers in Psychiatry found that the pooled prevalence of PTSD among displaced people across the continent was nearly 56%. Individual studies found rates as high as 78% in Nigeria and 77% in Zambia among displaced groups. Uganda and Ethiopia also showed prevalence above 48%. These figures dwarf anything seen in national-level surveys from high-income countries, yet they rarely appear in global rankings because they come from targeted studies of vulnerable populations rather than nationwide surveillance systems.
What the Rankings Actually Measure
Global mental health rankings are built on data that countries self-report or that researchers estimate using modeling. The Global Burden of Disease study, which produces the most widely cited numbers, combines survey data, hospital records, and statistical modeling to fill gaps. Countries with better data infrastructure get more accurate estimates. Countries with poor data get rougher approximations that tend to undercount.
This means the question of which country “has” the highest rate of mental illness is really a question about which country best measures it. The Netherlands, Portugal, and Australia invest heavily in mental health research, maintain detailed health registries, and have populations that are relatively willing to report symptoms. Nations in sub-Saharan Africa, South Asia, and parts of Southeast Asia almost certainly have substantial undiagnosed mental illness that never makes it into the data.
Anxiety and Depression Drive the Numbers
Across every country that ranks highly, anxiety disorders and depression are the two largest contributors. These conditions account for the majority of diagnosed mental illness worldwide and are responsible for the greatest share of disability. Among people under 24, both anxiety and depression are projected to keep rising through at least 2025, even as the overall burden of mental disorders in young people is expected to gradually decline through 2050.
This split matters. The total number of people with any mental health condition may stabilize or fall in coming decades thanks to better treatment access. But the two most common conditions, anxiety and depression, are trending upward in younger populations globally. For countries already at the top of the rankings, that trajectory suggests prevalence rates are unlikely to drop soon.