Carcass wrote:
He was constantly haunted by his own self-defeating impulses and tendency toward capriciousness, and could not escape his downward spiral into utter (i) _______ as his time, energy, and resources were squandered on useless pursuits.
A. guile
B. encomium
C. magnanimity
D. dissipation
E. deference
Kudos R.A.E.
I think, the sentence means that he was afraid by his own mercurial nature, and due this, he fell in abysmal (deep trap) by wasting time and energy.
Hence, dissipation is correct.
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Let me know if I am wrong.