Mixed cognitive-affective disturbances in the elderly: a new classification.

A new classification for mixed cognitive-affective disorders in the elderly is proposed. In Type 1, patients have depression as their only diagnosis, and the cognitive impairment resolves with treatment for the affective disorder. In Type 2, patients have two diagnoses--depression and dementia--and when the depression is treated, there is usually improvement in mood but not in cognitive ability. A review of the literature suggests that the number of Type 1 cases has been overestimated, and the number of Type 2 cases, underestimated.