Compulsion?

com·pul·sion
kəmˈpəlSHən
noun

Definition:
An urge to behave in a certain irresistible way, especially against one's conscious wishes.

Sentence:
"Bryan felt a sudden urge to keep moving forward even though his brain had wanted him to stop, he was under compulsion. "

Synonyms: urge, impulse, need, desire, drive etc.

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