We evaluated the effects of the 3 cognitive interventions fielded in the Advanced Cognitive Training for Independent and Vital Elderly study on 2 subsets of participants-1,606 without and 424 with suspected clinical depression at baseline. In the former group, only the speed of processing (vs. no-contact control) intervention had a significant effect, with its participants being 38% less likely to develop suspected clinical depression at 1 year (adjusted odds ratio = 0.62; p < .01). None of the interventions had a significant effect on recovery from suspected clinical depression in the latter group. Although the etiological mechanism of the speed of processing's protective effect was not isolated, it may result from successful adaptation to age-related changes through selective optimization with compensation.