Disrupts the lives of millions of peopleDepressive disorders. The Merck Manuals: The Merck Manual for Healthcare Professionals. http://www.merckmanuals.com/professional/psychiatric_disorders/mood_disorders/depressive_disorders.html#top. Accessed Nov. 28, 2011.Depression often looks different in men and women, and in young people and older adults. An awareness of these differences helps ensure that the problem is recognized and treated.