In Lindemann's theory, acute grief had six stages and the course of the stages lasted about six weeks, roughly one week per stage. The symptoms that are identified as belonging to acute grief are:
Feeling a tightness in the throat
Choking and shortness of breath
Feeling a painful tension
Empty feeling in abdomen (Dallas Baptist university)
The stages of acute grief are disordered sleep; absent thoughts, preoccupation; guilt; hostility; behavioral alterations; identification with the deceased.