Which mood disorder is most common in North America?

The one mood disorder that is predominant in American society is major depressive disorder. This chronic illness is twice as common in women and accrues a considerable morbidity. Women between the ages of 18 and 45 comprise the majority of those with major depression.  Depression also has a venomous blow on the economy, both in reduced productivity and more consumption of limited health care resources. In the workplace, depression is a principal cause of absenteeism and diminished productivity.