Depression is many things: a normal reaction to situations of loss and injury that subsides on its own; the main component—but in different guises—of several mood disorders, including major depressive disorder and dysthymic disorder (chronic low-grade depression); and one of the two major mood shifts away from normal in bipolar disorder. It also occurs as Seasonal Affective Disorder, Post-Partum Depression, and in tandem with other disorders. Therefore, discussing facts and statistics about depression needs to be done with care in order not to overstate or understate the actualities.
In July of 2011, a report generated by data from the World Health Organization (WHO) World Mental Health (WMH) Survey Initiative found that 121 million people around the world were being affected by depression, which is held to be responsible for 850,000 each year. The prevalence of depression was found to be 15 percent of populations in countries with high incomes and 11 percent for countries with low to middle income experiencing depression over the course of a lifetime. Overall 5.5 percent of the population of the world was depressed in the past year. The countries with the highest rate of Major Depressive Episodes (MDE) in the past year were the U.S., France, India, and the Netherlands. China had the lowest incidence in that time period.
Let’s now focus our discussion on the U.S. and divide our discussion into a look at adults on the one hand and adolescents and children on the other hand. Facts come from the National Institutes of Mental Health website.
Adult Depression Facts
Major Depressive Disorder
- In the years 2004 to 2008, between 6.4 and 7.9 percent of the adult population of the U.S. suffered from major depression.
- In each year, 2005 to 2008, women suffered at a higher rate than men did. While men’s prevalence of depression ranged from 4.6 (in 2008) to 5.3 (in 2006 and 2007), women’s prevalence ranged from 8.1 (in 2008) to 9.5 (in 2007).
- Over the course of a lifetime, women are 70 percent more likely than men to experience depression.
- Black without Hispanic background are 40 percent less likely than whites without Hispanic background to experience depression during their lives.
- In a 12-month period, adults aged 18 to 29 are 200 percent more likely to experience depression than those who are older than 60. Adults aged 30 to 44 are 80 percent more likely to experience depression than those who are older than 60.
- Just over half (51.7 percent) of those with the disorder are receiving treatment.
- The average age of onset for major depressive disorder is 32.
- Overall, 2.6 percent of the adult U.S. population has bipolar disorder.
- The average age of onset of bipolar disorder is 25.
- The lifetime prevalence of bipolar disorder is highest for 18 to 29 year olds (5.9 percent) and lowest for those over 60 (1 percent)
- Just under half (48.8 percent) of those with the disorder are receiving treatment.
- Approximately 1.5 percent of the adult U.S. population has dysthymic disorder.
- The average age of onset of dysthymic disorder is 31.
- The lifetime prevalence of dysthymic disorder is highest for 45 to 59 year olds (3.7 percent). It is lowest for those over 60 (1.3 percent).
- Over 61 percent of those with the disorder are receiving treatment.
Depression Facts for Adolescents and Children
Major Depressive Disorder
- In each year 2004 to 2008, between 7.9 and 9.0 percent of the US population of 12 to 17 year olds suffered from major depression.
- Girls are nearly three times more likely to experience depression than boys are (12.4 percent compared to 4.3 percent).
- While 3.9 percent of 12 year olds are depressed, 11.6 percent of 16 year olds are depressed, and 10.6 percent of 17 year olds are depressed.
- Bipolar disorder is rare among children, making facts and statistics about it scarce and not definitively reliable.
Teen depression statistics are not kept separately for Major Depressive Disorder and Dysthymic disorder in the report on the NIMH site.