Depression: History, Prevalence, and Economic Impact

History of Depression Diagnosis

Depressive symptoms were observed and recorded by Babylonians long before a specific word for a grouping of symptoms was employed (Reynolds & Wilson, 2013). The term melancholia, which is the historical term associated with depressed mood, once referred to various types of quiet insanity (Paykel, 2008). Hippocrates, who considered the etiology of depression as involving black bile, first documented melancholia.  It was not until the 19th century that depression was more specifically recognized as a collection of mood disorders. In the 1930s, official diagnostic criteria were developed, and a further distinction between unipolar and bipolar depression occurred in the 1960s (Paykel, 2008). 

Anxiety was regarded as the predominant mental health concern throughout mid-century (1950s-1960s) America (Horwitz, 2010). Psychological symptoms were conceptualized through a post World War II cultural lens and viewed as a response to the stress of modern life. Therefore, available psychiatric drugs also targeted anxiety.  In 1952, the first Diagnostic and Statistical Manual of Mental Disorders (DSM), the beginnings of a detailed classification system for psychiatric conditions, was published. In both the first and second editions of the DSM, depression was thought to serve as a defense mechanism to that masked anxiety as the real underlying condition (Horwitz, 2010).

Factors Impacting Prevalence

Understanding how depression rates have changed over time presents some challenging statistical problems. For example, one study found that changes in usage of diagnostic language could artificially inflate prevalence (Murphy et al., 2000). The study found that prevalence of depression remained stable at approximately 5%, over a period of 40 years from 1952-1992. 

More recent data provided by the World Health Organization (WHO) found an increase of over 18% prevalence in depression rates between 2005 and 2015 (WHO, 2017). This increase was attributed to population growth as well as a larger number of people belonging to age groups disproportionately affected by depression. According to WHO statistics, globally, depression rates are higher in females (5.1%) than males (3.6%). Males living in the Western Pacific Region demonstrate the lowest depression prevalence (2.6%), while females in the African Region demonstrate the highest prevalence (5.9%). Age is an additional variable impacting depression, with older adults of both genders experiencing significantly increased prevalence—7.5% for females and 5.5% for males aged 55-74. 

Generational factors also appear to be at play in impacting which age groups have higher prevalence of mental illness. Over the last decade, depression rates more than doubled in adolescents (52%) and young adults (63%), while adults in older age groups have not demonstrated similar increases (Twenge et al., 2019). The authors suggested the widespread use of technology and its impact on sleep may explain these results, rather than more stable factors such as economics or genetics (Mental Health Issues Increased, 2019). 

Economic Impact

The economic impact of depression is far-reaching and not limited to costs associated with seeking healthcare. Depression also directly impacts employees and businesses by decreasing productivity. In the U.S., the yearly overall costs of depression average $210 billion. However, about 60% of this sum is related to secondary costs associated with depression, such as comorbid physical and mental health issues, absenteeism, presenteeism, and suicide (Greenberg, 2015). Economic costs directly related to depression also include diagnosis, treatment, and long-term disability (Grazier, 2019)


Continued work attendance when an employee feels unable to be fully present and functional due to depression (presenteeism) globally incurs costs between 500% and 1000% higher than simply not going to work at all.  It comes as no that costs of presenteeism in the U.S. ranked second highest out of eight Eastern and Western countries (Evans-Lacko & Knapp, 2016). Companies lose an average of $44 billion in productive time each year, and 81% of this cost is explained by reduced productivity (Stewart et al., 2003). Given rates of inflation, current economic impact on businesses is likely much higher. By improving workplace mental health, employers can not only help their workers, but also improve the financial health of their company. A 2014 report found that for every dollar spent on improving mental health, companies earned back the equivalent of $2.30 in benefits such as increased productivity and fewer compensation claims (PricewaterhouseCoopers, 2014). Clearly, the benefits of addressing depression in the workplace far outweigh potential costs.


Evans-Lacko, S., & Knapp, M. (2016). Global patterns of workplace productivity for people with depression: Absenteeism and presenteeism costs across eight diverse countries. Social Psychiatry and Psychiatric Epidemiology, 51, 1525-1537. https://doi.org/10.1007/s00127-016-1278-4

Grazier K.L. (2019) The Economic Impact of Depression in the Workplace. In: Riba M., Parikh S., Greden J. (eds) Mental Health in the Workplace. Integrating Psychiatry and Primary Care. Springer, Cham. https://doi.org/10.1007/978-3-030-04266-0_2

Greenberg, P. E. (2015, February 25). The growing economic burden of depression in the U.S. Scientific American. https://blogs.scientificamerican.com/mind-guest-blog/the-growing-economic-burden-of-depression-in-the-u-s/

Horwitz, A. V. (2010). How an age of anxiety became an age of depression. Milbank Quarterly, 88(1), 112-138. https://dx.doi.org/10.1111%2Fj.1468-0009.2010.00591.x

Murphy, J. M., Laird, N. M., Monson, R. R., Sobol, A. M., & Leighton, A. H. (2000). The Stirling County Study. Archives of General Psychiatry, 57(3), 209-215. https://dx.doi.org/10.1001/archpsyc.57.3.209

Paykel, E. S. (2008). Basic concepts of depression. Dialogues in Clinical Neuroscience, 10(3), 279-289. https://dx.doi.org/10.31887%2FDCNS.2008.10.3%2Fespaykel

PricewaterhouseCoopers. (2014). Creating a mentally healthy workplace: Return on investment analysis. https://www.headsup.org.au/docs/default-source/resources/beyondblue_workplaceroi_finalreport_may-2014.pdf

Reynolds, E. H., & Wilson, J. K. (2013). Depression and anxiety in Babylon. Journal of the Royal Society of Medicine, 106(12), 478-481. https://doi.org/10.1177%2F0141076813486262

Stewart, W. F., Ricci, J. A., Chee, E., Hahn, S. R., & Morgenstein, D. (2003). Cost of lost productive work time among US workers with depression. Journal of the American Medical Association, 289(23), 3135-3144. https://doi.org/10.1001/jama.289.23.3135

Mental health issues increased significantly in young adults over the last decade. (2019, March 15). ScienceDaily. https://www.sciencedaily.com/releases/2019/03/190315110908.htm

Twenge, J. M., Cooper, A. B., Joiner, T. E., Duffy, M. E., & Binau, S. G. (2019). Age, period, and cohort trends in mood disorder indicators and suicide-related outcomes in a nationally representative dataset, 2005–2017. Journal of Abnormal Psychology, 128(3), 185–199. https://doi.org/10.1037/abn0000410

World Health Organization (2017). Depression and other common mental disorders: Global health estimates. Retrieved from 


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