What We Seem to Have Forgotten: Health and Disease in the Modern World

As a physician, I support science and modern medicine while also valuing faith and spirituality. My goal here is to encourage reflective consideration. So, use this article to think critically, rather than fueling polarized debate.

A hundred years ago, life might sound, at first, like something to envy. There were no processed foods stacked in supermarkets, no high-fructose corn syrup in our beverages, no artificial sweeteners in our coffee, no artificial preservatives hidden in labels, and no fast-food chains luring families into unhealthy habits. People ate what came fresh from the farm or the market, local, home-grown vegetables pulled from the ground, milk from nearby cows, and bread baked daily. The air was cleaner, free from the exhaust of highways and jets, and families gathered on front porches rather than screens. There was no social media to distract, compare, or inflame; neighbors and relatives were the center of social life. To modern ears, the picture feels like a lost paradise: wholesome, natural, and free of the toxins and stressors that seem to plague us today.

However, the illusion of paradise concealed a harsher reality. In 1900 to 1925, infant and child death shaped every family’s reality. In the United States, infant mortality was roughly 100 deaths per 1000 live births in the early 20th century—90% greater than today. In some cities, as many as 30% of infants died younger than 1 year old. Maternal mortality was also nearly 99% higher across the century. Drops in these rates stemmed from access to clean water and sanitation, safer childbirth practices, vaccines, and, crucially, medications and antibiotics.^1,2

Even for those who survived infancy, adulthood was shadowed by threats modern medicine now controls, such as appendicitis without safe surgery, diabetes without insulin, and wound or lung infections without effective drugs. Tuberculosis was a routine killer in the 19th and early 20th centuries. Vaccines later crushed childhood epidemics: diphtheria caused 13,000 to 15,000 US deaths annually in the 1920s.² Smallpox, one of the most feared diseases in history, killed 300 to 500 million in the 20th century alone before eradication; it struck children especially hard and left survivors scarred or blind.^3,4

When Everything Changed

The leap in life expectancy was not only gradual—it had turning points that felt almost overnight. The most dramatic was the era of antibiotics. When penicillin transitioned from a lab curiosity in 1928 to mass-produced therapy in the early 1940s, fatal infections shifted from foregone conclusions to treatable illnesses. Contemporary and later clinical reviews document the transformation; meningitis, sepsis, and pneumonias, once uniformly deadly, began to see survival as the norm.^5,6

Vaccines rewrote childhood. Routine immunization against diphtheria (1940s), polio (1950s), and measles (1960s) transformed seasons of funerals into celebrations of school plays and graduations. Before the measles vaccine scale-up, approximately 2.6 million deaths annually were attributed to measles; with global immunization, deaths fell below 100,000 in 2016 (though they have risen again where vaccine coverage slipped).^7,8

The Irony of Mistrust

Here is the irony: In 2025, with global life expectancy of approximately 73 years (and over 80 in many wealthy nations), a growing minority questions the very tools that have granted us this longevity: vaccines and medications.

Because most people alive today have never watched a sibling die of diphtheria, a neighbor’s child of pertussis, or a postpartum fever take a new mother, the achievements of medicine become invisible. The success of science erased the day-to-day memory of its necessity. 

It is as if some, if not many, in today’s society believe we have always lived with these long life expectancies and that our recent access to modern medicine is instead causing harm.

Despite recent periods of condemnation towards medicine and its providers, global life expectancy has continued its long-term rise, reaching 73.4 years in 2019, before dropping by approximately 1.6 years during the COVID-19 pandemic, marking the first global decline in decades and demonstrating the impact on life expectancy when proper treatments are unavailable.⁹ Since 2021, however, life expectancy has begun to recover and overall remains higher than it was at the start of the 2010s, reflecting sustained gains in public health and medicine despite the pandemic shock.^10,11

Growing mistrust in modern medical advancement is, in part, a generational memory problem. Most living adults did not experience the Great Depression, breadlines, a world-scale war, the draft, premature deaths of parents and relatives from illnesses, or routine child funerals. Without those scars and memories, survival feels like a baseline entitlement, not a precarious achievement. When antibiotics reduce a life-threatening infection to an inconvenience, it is easy to assume that natural life has always been this safe.

Longevity and the Gene Pool—Why Do We See More Physical and Mental Health Diagnoses?

Modern medicine has not just prolonged life; it has improved life’s quality. People with chronic physical conditions (diabetes, heart disease, cancer) often live decades longer. Equally transformative is mental health care. Conditions that once meant institutionalization or severe disability, such as major bipolar disorder and schizophrenia, can often be effectively managed to the point of sustained work, fruitful relationships, and responsible parenting. This fact also has population-level consequences. When survival and stability improve, more people with heritable vulnerabilities form intimate relationships and have children, passing along those physical and mental health genes to their offspring and expanding the genetic pool for those specific traits, potentially increasing their prevalence.

Meanwhile, diagnosis and treatment rates have risen sharply: age-standardized global rates of many mental disorders have been relatively stable since 1990, but the absolute number of cases and Disability-Adjusted Life Years (DALYs) has grown substantially with population growth, survival, and better detection; United States surveys also show rising self-reported distress and greater mental-health service use. In youth and young adults, high numbers of cases are now clearly documented worldwide.^12-15

The Global Burden of Disease study conducted the most comprehensive analysis to date of mental health burden across 204 countries between 1990 and 2019.¹⁵ The study examined 12 key mental disorders:depressive disorders, anxiety disorders, schizophrenia, bipolar disorder, autism spectrum disorders, attention-deficit/hyperactivity disorder, conduct disorder, eating disorders, idiopathic developmental intellectual disability, alcohol use disorder, drug use disorders, and other mental disorders. Results showed that while age-standardized prevalence rates remained largely stable over 3 decades, the absolute number of individuals affected and total DALYs rose substantially due to global population growth, as well as genetic risk factors and aging. This underscores the persistent and growing impact of mental illness worldwide despite stable per-person risk. The greater total number of cases despite stable prevalence rates supports the spread of predisposing genetic factors in the population, as individuals with physical and mental health conditions live better lives than in the past and are more likely to have opportunities to reproduce.

A Hard Truth

Life expectancy reveals the truth: from ~35 years in 1825, ~58 years in 1925, to over 73 years today, with even higher averages in many countries.¹⁷ These gains stem not from a simpler past or organic food, but from public health advances and medical science such as penicillin, vaccines, and safer medical care, shifting mortality from youth to old age.

So yes, fresh air and farm meals are lovely. But a century ago, before modern medicine, while daily life seemed simpler, you might also have buried your 2 children and died yourself¾in what we now call middle age. Modern medicine has given us the gift and burden of longevity; today, we confront wholly new challenges: ones that test what we do with the time we have been given.

Dr DeSarbo is the medical director and neuropsychiatrist at ED-180 Treatment Programs. He is also the author of the book The Neuroscience of a Bucket List.

References

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4. About smallpox. Centers for Disease Control and Prevention. October 22, 2024. Accessed October 3, 2025. https://www.cdc.gov/smallpox/about/index.html

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17. Kinsella KG. Changes in life expectancy 1900–1990. Am J Clin Nutr. 1992;55(6 Suppl):1196S-1202S.