Grief is a multi-faceted response to loss. It includes the emotional numbness, disbelief, separation, anxiety, despair, sadness, and lonliness that accompany the loss of someone that is loved. Although conventionally focused on the emotional response to loss, it also has physical, cognitive, behavioral, social, and philosophical dimensions. Common to human experience is the death of a loved one, whether it be a friend, family, or other companion. While the terms are often used interchangeably, bereavement often refers to the state of loss, and grief to the reaction to loss. Losses can range from loss of employment, pets, status, a sense of safety, order, or possessions, to the loss of loved ones. Our response to loss is varied and researchers have moved away from conventional views of grief (that is, that people move through an orderly and predictable series of responses to loss) to one that considers the wide variety of responses that are influenced by personality, family, culture, and spiritual and religious beliefs and practices.

Bereavement, while a normal part of life for us all, carries a degree of risk when limited support is available. Severe reactions to loss may carry over into familial relations and cause trauma for children, spouses and any other family members: there is an increased risk of marital breakup following the death of a child, for example. Issues of personal faith and beliefs may also face challenge, as bereaved persons reassess personal definitions in the face of great pain. While many who grieve are able to work through their loss independently, accessing additional support from bereavement professionals may promote the process of healing. Grief counseling, professional support groups or educational classes, and peer-led support groups are primary resources available to the bereaved. In the United States, local hospice agencies may be an important first contact for those seeking bereavement support.

Stage theories and processes

Bowlby and Parkes both note psychophysiologic components of grief as well. Included in these processes are feelings of unreality, depersonalization, withdrawal, and an anesthetizing of affect. The person feels unable to come to terms with what just occurred. "Whenever one's identity and social order face the possibility of destruction, there is a natural tendency to feel angry, frustrated, helpless, and/or hurt. The volatile reactions of terror, hatred, resentment, and jealousy are often experienced as emotional manifestations of these feelings." (see the article entitled The Grieving Process by Michael R. Leming and George E. Dickinson) Disorganization and despair are the processes commonly associated with bereavement: the mourning and severe pain of being away from the loved person or situation. Reorganization is the assimilation of the loss of something or someone and redefining of life and meaning without the person that has been lost.