The objective of this study is to find possible links between bereavement, depression, and the immune system. This study will follow a group of elderly bereaved spouses and a group of elderly people who have not lost a long-term spouse. The group of bereaved individuals will be followed for approximately 13 months after the loss of their spouse and the group of controls will be followed for 13 months after entering the study. Researchers will make note of any clinical, biological, and immunological changes in any participants of the study.