Such distress can be accompanied by crying; sighing; having dreams, illusions, and even hallucinations of the deceased; and seeking out things or places associated with the deceased individual. Some bereaved people will experience anger, will protest the reality of the loss, and will have significant periods of sadness, despair, insomnia, anorexia, fatigue, guilt, loss of interest, and disorganization in daily routine.
Many bereaved persons will experience highly intense, time-limited periods (e.g., 20–30 minutes) of distress, variously called grief bursts or pangs. Sometimes these pangs are understandable reactions to reminders of the deceased person, and at other times they seem to occur unexpectedly.
Over time, most bereaved people will experience symptoms less frequently, with briefer duration, or with less intensity. Although there is no clear agreement on any specific time period needed for recovery, most bereaved persons experiencing normal grief will note a lessening of symptoms at anywhere from 6 months through 2 years postloss. Normal or common grief appears to occur in 50% to 85% of persons following a loss, is time-limited, begins soon after a loss, and largely resolves within the first year or two.
Stage Models of Normal Grief
A number of theoretically derived stage models of normal grief have been proposed.[14,15,16,17] Most models hypothesize a normal grief process differentiated from various types of complicated grief. Some models have organized the variety of grief-related symptoms into phases or stages, suggesting that grief is a process marked by a series of phases, with each phase consisting of predominant characteristics. One well-known stage model, focusing on the responses of terminally ill patients to awareness of their own deaths, identified the stages of denial, anger, bargaining, depression, and acceptance. Although widely used, this model has received little empirical support.
A more recent stage model of normal grief  organizes psychological responses into four stages: numbness-disbelief, separation distress, depression-mourning, and recovery. Although presented as a stage model, this model explains "it is important to emphasize that the idea that grief unfolds inexorably in regular phases is an oversimplification of the highly complex personal waxing and waning of the emotional process." Bereavement researchers have found empirical support for this four-stage model, although other researchers have questioned these findings.[19,20]