| Prevalence |
Approximately 10–25% of women and 5–12% of men will develop MDD over their lifetimes, although some studies find even higher rates (Rhode et al., 2013). Before puberty, however, boys and girls develop MDD in equal numbers (Kessler et al., 2003). People with different ethnic backgrounds, education levels, incomes, and marital statuses are generally afflicted equally (Kessler et al., 2003; Weissman et al., 1991). |
| Comorbidity |
Most people with MDD also have an additional psychological disorder (Rush et al., 2005), such as an anxiety disorder (Barbee, 1998; Kessler et al., 2003) or substance use disorder (Rush et al., 2005). |
| Onset |
MDD can begin at any age, with the average age of onset in the mid-20s, although people are developing MDD at increasingly younger ages (Rhode et al., 2013). |
| Course |
Among people who have had a single MDE, approximately 50–65% will go on to have a second episode (Angst et al., 1999; Solomon et al., 2000). Those who have had two episodes have a 70% chance of having a third, and those who have had three episodes have a 90% chance of having a fourth. |
| Gender Differences |
Women are approximately twice as likely as men to develop MDD (Kessler, 2003; Rhode et al., 2013). Some women report that depressive symptoms become more severe premenstrually. |
| Unless otherwise noted above, the source for information is American Psychiatric Association, 2013. |