Adam Clarke on Mark 1:26

And when the unclean spirit had torn him - And had thrown him down in the midst, Luk 4:35, και σπαραξαν, and convulsed him. Never was there a person possessed by an unclean spirit who did not suffer a convulsion, perhaps a total ruin of nature by it. Sins of uncleanness, as the apostle intimates, are against the body; they sap the foundation of life, so that there are very few of this class, whether male or female, that live out half their days: they generally die martyrs to their lusts. When the propensities of the flesh are most violent in a person who is determined to serve God, it is often a proof that these are the last efforts of the impure spirit, who has great rages because he knows his time is but short.