The research team, led by Lars Jacob Stovner of the Norwegian University of Science and Technology together with Ann Kristin Skrindo Knudsen, Lars Lien, Henrik Peersen, and Nils Erik Gilhus, extracted and summed GBD 2023 estimates for more than two dozen conditions, from Alzheimer’s disease and stroke to anxiety, depression, migraine, epilepsy, and addiction. Because the GBD framework has no single “brain disorders” category, the authors combined the individual diagnoses themselves, drawing on data from the Norwegian Cause of Death Registry, patient registries, and epidemiological surveys processed through GBD’s Bayesian meta-regression tool, DisMod-AT. The scale of the data effort is considerable: GBD 2023 drew on more than 100,000 data sources worldwide to generate internally consistent estimates of prevalence, incidence, and mortality for every age group, sex, and location.

The headline numbers reveal a critical asymmetry. Brain disorders were responsible for 30.77 percent of all years lived with disability (YLDs) but only 22.31 percent of all years of life lost (YLLs). In other words, these are primarily conditions people live with rather than die from, which makes them especially consequential from a socioeconomic standpoint. Mental disorders were the single largest contributor to disability, accounting for 17.56 percent of all YLDs, with anxiety disorders alone responsible for 7.35 percent. Headache disorders, dominated by migraine, contributed another 4.91 percent of all YLDs, affecting half the population in any given year. When it comes to mortality, neurological disorders dominate, chiefly because of Alzheimer’s disease and dementia, which alone accounted for 5.47 percent of all years of life lost.

The study is also the first to track how the total burden of brain disorders has shifted over time in a single country. Comparing age-standardized rates from 1990 to 2023, the researchers found a tale of two very different trajectories. On the positive side, the burden of stroke fell dramatically, with DALY rates down 65 percent over the 34-year period. This decline reflects a genuine reduction in incidence of 52 percent, alongside a 71 percent drop in mortality, driven by falling smoking rates, better control of blood pressure and cholesterol, improved diabetes management, faster acute stroke treatment, and more targeted rehabilitation. Alcohol use disorder prevalence fell 43 percent, and meningitis, once a feared killer, saw its DALY rate collapse by 89 percent thanks to vaccination and antimicrobial therapy. There were even modest, though statistically uncertain, reductions in the prevalence and burden of Alzheimer’s disease and dementia, a trend that mirrors observations elsewhere in the world and is plausibly linked to improving cerebrovascular health across generations.

Against these successes stand several deeply worrying counter-trends. The most dramatic is Parkinson’s disease, for which age-standardized prevalence rose 271 percent and incidence rose 115 percent over the study period, producing a 43 percent increase in DALY rates and an extraordinary 263 percent increase in years lived with disability. The authors note that better survival and improved diagnosis may explain part of this rise, since mortality increased far less than prevalence, but they cannot fully account for the steep increase in incidence itself. Possible contributors under investigation include environmental toxicants and even the decline of smoking in industrialized countries, a protective factor in Parkinson’s. Identifying the preventable causes of this rise, the researchers argue, should be a high scientific priority.

Mental disorders show no such improvement and, in aggregate, grew substantially. Overall mental disorder prevalence rose 29 percent, driven mainly by anxiety disorders (up 57 percent), depressive disorders (up 26 percent), and eating disorders (up 18 percent). Anxiety disorders alone saw DALY rates climb 58 percent, making them the single largest level-3 brain disorder contributor to overall disease burden in Norway at 3.79 percent of all DALYs. None of the major mental disorders showed improvement over three decades, and the authors point to shifting diagnostic practices, increased awareness, and the documented rise in mental health problems among young girls as likely contributing factors. Similar trends have been reported in the United Kingdom, suggesting the pattern is not unique to Norway. Compounding the concern, drug use disorders went in the opposite direction to alcohol, with prevalence up 23 percent and mortality from drug use soaring 97 percent, a trend the authors link partly to the increasing availability of potent synthetic opioids and poly-substance abuse.

The methodology behind these estimates deserves attention, both for its power and its limitations. GBD quantifies health loss by multiplying disease prevalence by disability weights derived from community surveys of tens of thousands of people across many countries, scaled from zero to one. Years of life lost are calculated against the highest observed life expectancy globally, ensuring that no population is penalized for biology alone. Crucially, the GBD framework corrects for comorbidity in a multiplicative rather than additive fashion, so summing individual conditions to estimate the total brain disorder burden does not inflate the result. Yet the authors are candid that many Norwegian figures rest on extrapolations from neighboring and epidemiologically similar countries, and that residual bias from changing diagnostic definitions cannot be excluded. Some categories, notably autism spectrum disorder and central nervous system cancers, carry uncertainty intervals so wide that no firm trend conclusions can be drawn, and neurotrauma had to be excluded from the total burden entirely because GBD reports injuries by cause rather than anatomical site, meaning the reported figures are minimum estimates.

The socioeconomic implications extend well beyond healthcare budgets. Many of the most common brain disorders, including ADHD, migraine, epilepsy, multiple sclerosis, schizophrenia, and depression, strike in childhood, adolescence, or early adulthood, precisely the years when people build careers, relationships, and families. Early-onset conditions reduce workforce participation, generating costs through disability pensions, absenteeism, and reduced productivity at work, while their cumulative effects ripple through later life outcomes including marriage, careers, and child-rearing. Conditions that appear later in life, such as dementia, Parkinson’s disease, and stroke, impose a different but equally heavy load: intensive caregiving demands on relatives and mounting pressure on nursing home capacity. With Norway’s population continuing to age, the total number of stroke and dementia patients will likely remain high even as age-specific rates decline.

The message for policymakers is clear and double-edged. Where prevention and treatment have been effective, the data show measurable, decades-long improvements, as stroke and meningitis demonstrate. But for anxiety, depression, and headache disorders, three of the most burdensome conditions in the entire analysis, thirty years have delivered essentially no progress, and for Parkinson’s disease and drug use disorders the situation is actively deteriorating. The GBD study identifies few modifiable risk factors for mental disorders, underscoring how much basic research remains to be done. The authors urge continued monitoring of brain health through future GBD iterations, arguing that only systematic measurement can evaluate the real-world impact of new and often very costly treatments, pinpoint emerging threats before they become crises, and direct scarce research and healthcare resources to where they will save the most healthy years of life. As Norway’s experience shows, the brain is both the greatest single source of health loss in a modern welfare state and, until now, one of its most fragmented and neglected policy priorities.

Subject of Research: The national burden of neurological, mental, and substance use disorders in Norway and their trends from 1990 to 2023 using Global Burden of Disease Study 2023 data.

Article Title: The burden of brain disorders in Norway: an analysis of data from the global burden of disease study 2023

Article References: Stovner, L. J., Skrindo Knudsen, A. K., Lien, L., Peersen, H., & Gilhus, N. E. (2026). The burden of brain disorders in Norway: an analysis of data from the global burden of disease study 2023. The Lancet Regional Health – Europe, 70, Article 101857. https://doi.org/10.1016/j.lanepe.2026.101857

Image Credits: AI Generated

DOI: 10.1016/j.lanepe.2026.101857

Keywords: brain disorders, disease burden, DALYs, Norway, Global Burden of Disease, mental health, neurological disorders, Parkinson's disease, stroke, anxiety disorders, substance use, disability