Affective states in normal and depressed older people.

Ratings on a 10-item affect checklist yielding composite positive affect and negative affect scores were made daily for 30 days by older people in residential care: 19 were diagnosed as having major depression, 21 had minor depression, and 37 were without psychiatric diagnosis ("normal"). Mean levels of positive affect were highest in normal people and least in those with major depression; negative affect was lowest in normal ones and highest in those with a major depression. Variability was least among those with major depression in positive affect and among normal people in negative affect, while residents with minor depression showed some tendency, although inconsistent, toward greater day-to-day variability in positive affect. Patterns of invariance were such that those with major depression tended to be consistently lacking in positive affect but were variable in negative affect; normal people showed variability in positive affect but a relatively unvarying lack of negative affect. Clinical major depression was thus characterized less by "pervasive" depressive affect than by anhedonia.