concepts
Depression is a pervasive psychosocial problem that is a constellation of cognitive (e.g., difficulty concentrating), vegetative (e.g., loss of appetite), and affective (e.g., sad mood) symptoms. About 10 to 15 percent of the population will experience an episode of clinical depression at some point in their lives, and far more will suffer from subclinical levels of depression. [Source: Encyclopedia of Human Relationships; Depression and Relationships]
depression and relationships
emotion processes in relationships