Not everyone experiences what Lindemann described. Still, many people, especially those faced with a sudden death, will show some of these signs in their grieving process. It is not uncommon for people with acute grief to feel like they are going crazy and that it is only going to get worse. Grief can also leave one open to physical sickness. Mourning is an expression of the bereaved person's sadness.
Different cultures mourn differently.
It is expected that a bereaved person grieves and that the signs are shown through mourning, but this is not always true. Death takes many forms and occurs throughout the lifespan. In many ways, American society fails to support the bereaved person. We need to better understand the processes of dying and grieving.