From Erich Fromm's Escape from Freedom (181-182):
It would seem that the amount of destructiveness to be found in individuals is proportionate to the amount to which expansiveness of life is curtailed. By this we do not refer to individual frustrations of this or that instinctive desire but to the thwarting of the whole life, the blockage of spontaneity of the growth and expression of man's sensuous, emotional, and intellectual capacities. Life has an inner dynamism of its own; it tends to grow, to be expressed, to be lived. It seems that if this tendency is thwarted the energy directed toward life undergoes a process of decomposition and changes into energies directed toward destruction. In other words: the drive for life and the drive for destruction are not mutually independent factors but are in a reversed interdependence. The more the drive toward life is thwarted, the stronger is the drive toward destruction; the more life is realized, the less is the strength of destructiveness. Destructiveness is the outcome of unlived life. Those individual and social conditions that make for suppression of life produce the passion for destruction that forms, so to speak, the reservoir from which the particular hostile tendencies--either against others or against oneself--are nourished.