Definitions, Prevalence, and Treatment of Depression

Major depression is defined as a period of at least two weeks when a person experienced a depressed mood or loss of interest/pleasure in daily activities and had a majority of specified symptoms, such as sleep disruption, changes in eating patterns, decreased energy, concentration, and/or feelings of low self-worth.⁴¹ The estimated prevalence of at least one major depressive episode among U.S. adults was 8.3% in 2021 (21 million individuals) and was highest in adults aged 18-25 (18.6%). ⁴¹ Depression is more common in females than in males and rates vary worldwide.^28,29,41 Women are 1.5 to 3-fold more likely to be diagnosed with depression than men and they report higher rates of internalized symptoms (e.g. sadness, fatigue, somatic symptoms) compared with men who report higher rates of externalized behaviors, including anger and substance abuse.^41-43 Men, despite lower rates of diagnosis rates, have significantly higher rates of suicide. Treatment types include non-pharmacologic therapy with a health professional — including development of coping mechanisms and/or support systems, medication treatment, and/or a combination of both. ⁴⁴ The global 12-month/lifetime pooled treatment rate was 34.8% (95% confidence interval: 29.9, 39.9%)⁴³ The treatment rates were 48.3% (43.0, 53.6%) in high-income countries, 21.4% (15.1, 27.7%) in middle-income countries, and 16.8% (11.3, 23.0%) in low-income countries.⁴⁵ While depression and anxiety can be linked, they are not identical and reported depression prevalence worldwide does not align with those of anxiety, indicating that there are other factors that may play into the diagnosis of depression compared to anxiety.