Facts about depression in adults show that depression is the leading cause of disability for people ages 15 to 44 in the United States, according to the Anxiety and Depression Association of America. The median age for an onset of major depressive disorder is approximately 32.
Depression is more prominent in women than men, although the disorder can affect both genders at any age, explains the ADAA. As of 2015, approximately 6.7 percent of people 18 years of age and older in the United States suffer from major depressive disorder. Approximately one-half of people diagnosed with depression also suffer from an anxiety disorder.