Existential distress is defined as the psychological turmoil individuals may experience in the face of imminent death, which threaten individuals on a physical, personal, relational, spiritual, or religious level.
Morse in 1998 creates a more basic definition as "a deep concern over whether or not one is living a meaningful and fulfilling life".
People affected by serious illness usually experience suffering that goes further than the physical aspects of the body. Suffering especially in the face of a terminal illness will frequently extend to the mental, emotional and even spiritual.