The Kübler-Ross model, also known as the Five Stages of Grief, details the five stages through which people deal with grief and tragedy. Created by Elisabeth Kübler-Ross in the 20th century (specifically through her 1969 book On Death and Dying), terminally ill patients experience these stages.
The stages are:
Kübler-Ross stated that these stages are ones people go through with any loss, like divorce or the death of a loved one.
In 2372, Cantabrian commanding officer Noah Wrightson, infected with the often-fatal Caldean Acute Cardiopulmonary Syndrome, stated he didn't believe in the Kübler-Ross model. Cantabrian counselor Daniel Radke countered that the stages do exist and encouraged Wrightson to talk about dealing with his mortality in order to help him come to terms with his death. (Star Trek: The Cantabrian Expeditions: "Isolation")