Scicurious at Neurotic Physiology is publishing a bunch of “Back to Basics” posts that are well worth a read, and I found her series on depression particularly interesting. In Depression: Part 1, Scicurious explains why we should care about this disease:
Right now, depression is thought to occur in 21% of women and 13% of men worldwide, with 18 million people affected in the US (this is according to the lecture I had in 2006 on it, though other people say it’s 8-17% of the total population). It’s a big deal for research, depression is second leading cause of disability, and antidepressants are the third best-selling group of pharmocotherapies in the world. Not only that, the economic burden is 12.4 billion dollars a year in medical, psychiatric, and pharmacological care, and that’s not counting decreased productivity, work absences, and mortality costs for depression-related suicides (well, ok, it’s not that much when compared to the cost of the Iraq war). Regardless of its issues in modern society, depression is both a significant emotional and economic burden, and something that goes very far back in human history.
That got me interested in finding out a bit more about disability caused by depression.
In 1990, the World Health Organization published its first Global Burden of Disease study, which used information from member states to quantify the health effects of 100+ diseases and injuries. The report introduced the DALY – disability-adjusted life year – which the WHO defines as “the sum of years of potential life lost due to premature mortality and the years of productive life lost due to disability.” In 2004, they published an update, and the table of the leading causes of burden of disease is on page 44 of the PDF.
Worldwide, WHO found that depression (unipolar depressive disorders) is third on the list of diseases ranked by DALYs – it accounts for 4.3% of total DALYs. (Lower respiratory infections and diarrheal diseases come in first and second, accounting for 6.2% and 4.8% of DALYs, respectively.) The rankings differ when you look at countries grouped by income. In low-income countries, depression is eighth on the list, accounting for 3.2% of DALYs. In both middle-income countries and high-income countries, depression tops the list, accounting for 5.1% of DALYs in middle-income countries and 8.2% of DALYs in high-income countries.
Depression is a worldwide problem, and widespread successful treatment of depression would noticeably reduce the global burden of disability. To learn more about research into depression and the development of treatments, check out Scicurious’s fascinating posts on pharmacotherapies, how to study depression in rodents, the serotonin system, the serotonin theory of depression, and genetic vulnerabilities and predisposition for depressive disorders.