Many authors have proposed types of grief reactions.[1,2] Research has focused on normal and complicated grief while specifying types of complicated grief  and available empirical support  with a focus on the characteristics of different types of dysfunction. Controversy over whether it is most accurate to think of grief as progressing in sequential stages (i.e., stage theories) continues.[5,6] Most literature attempts to distinguish between normal grief and various forms of complicated grief such as chronic grief or absent/delayed/inhibited grief.[1,3,4]
Bereavement research has tried to identify these patterns by reviewing available empirical support  while also looking for evidence that these grief reactions are unique and not simply forms of major depression, anxiety, or post-traumatic stress.
Anticipatory grief refers to a grief reaction that occurs in anticipation of an impending loss. Anticipatory grief is the subject of considerable concern and controversy.
The term anticipatory grief is most often used when discussing the families of dying persons, although dying individuals themselves can experience anticipatory grief. Anticipatory grief includes many of the same symptoms of grief after a loss. Anticipatory grief has been defined as "the total set of cognitive, affective, cultural, and social reactions to expected death felt by the patient and family."
The following aspects of anticipatory grief have been identified among survivors:
- Heightened concern for the dying person.
- Rehearsal of the death.
- Attempts to adjust to the consequences of the death.
Anticipatory grief provides family members with time to gradually absorb the reality of the loss. Individuals are able to complete unfinished business with the dying person (e.g., saying "good-bye," "I love you," or "I forgive you").
Anticipatory grief cannot be assumed to be present merely because a warning of a life-threatening illness has been given or because a sufficient length of time has elapsed from the onset of illness until actual death. A major misconception is that anticipatory grief is merely conventional (postdeath) grief begun earlier. Another fallacy is that there is a fixed volume of grief to be experienced, implying that the amount of grief experienced in anticipation of the loss will decrease the remaining grief that will need to be experienced after the death.
Several studies [11,12] have provided clinical data documenting that grief following an unanticipated death differs from anticipatory grief. Unanticipated loss overwhelms the adaptive capacities of the individual, seriously compromising his or her functioning to the point that uncomplicated recovery cannot be expected. Because the adaptive capacities are severely assaulted in unanticipated grief, mourners are often unable to grasp the full implications of their loss. Despite intellectual recognition of the death, there is difficulty in the psychologic and emotional acceptance of the loss, which may continue to seem inexplicable. The world seems to be without order, and like the loss, does not make sense.