Of all the psychiatric disorders, depression is by far the most common, affecting between 8 and 18 percent of the general population at some point in their lives. Although the heterogeneity of the affective disorders makes it unlikely that a single set of factors can adequately explain the full range of phenomena associated with depression, there has been a swell of research over the past two decades designed to examine cognitive factors in the etiology, maintenance, and treatment of this disorder.
Whereas early work in this area tended to examine responses of depressed persons to...