Sentence:  [O]ur "high" or "academic" or "avant-garde" culture is in a state of crisis. This crisis is not a healthy one, but a <WSD>sickness unto death</WSD>, a decadence that threatens to destroy our society. 
Meaning of the word marked with <WSD> tags:  Despair, profound discontent, or a similar persistent debilitating malaise of the mind, spirit, or soul that produces a decline in mental, physical, or societal health and that may culminate in death or dissolution.