Depression

A kind of disorder which includes symptoms in mood, body, motivation and behavior area. The symptoms of this disorder are negative mood, loss of energy and interest, feeling of guilt, difficulty in concentration, reduction of appetite and thought of death and suicide.

Reference:
Hedayati, M., & Khazaei, M. (2014). An investigation of the relationship between depression, meaning in life and adult hope. 4th World Conference on Psychology, Counseling and Guidance WCPCG-2013, 598-601.