Grief (novel)
During the course of the novel, the ideas of the stages of grief are introduced. The stages are denial, anger, depression, and acceptance. The narrator, as well as other characters in the story, slowly passes through these stages in trying to deal with death.
Complicated grief disorder
In psychiatry, complicated grief disorder (CGD) is a proposed disorder for those who are significantly and functionally impaired by prolonged grief symptoms for at least one month after six months of bereavement. It is distinguished from non-impairing grief and other disorders (such as major depressive disorder and posttraumatic stress disorder). This disorder has been reviewed by the DSM-5 work groups, who have decided that it be called Persistent complex bereavement disorder and placed it in the chapter on Conditions for Further Study in the new DSM-5.