jagá¹›hus tad-visṛṣá¹Äá¹ tÄá¹
já¹›mbhaṇÄkhyÄá¹ tanuá¹ prabhoḥ
nidrÄm indriya-vikledo
yayÄ bhÅ«teá¹£u dṛśyate
yenocchiá¹£á¹Än dhará¹£ayanti
tam unmÄdaá¹ pracaká¹£ate
jagá¹›huḥ - took possession; tat-visṛṣá¹Äm - thrown off by him; tÄm - that; já¹›mbhaṇa-ÄkhyÄm - known as yawning; tanum - the body; prabhoḥ - of Lord BrahmÄ; nidrÄm - sleep; indriya-vikledaḥ - drooling; yayÄ - by which; bhÅ«teá¹£u - among the living beings; dṛśyate - is observed; yena - by which; ucchiá¹£á¹Än - smeared with stool and urine; dhará¹£ayanti - bewilder; tam - that; unmÄdam - madness; pracaká¹£ate - is spoken of.
The disease of insanity or being haunted by ghosts takes place in an unclean state of existence. Here it is clearly stated that when a man is fast asleep and saliva flows from his mouth and he remains unclean, ghosts then take advantage of his unclean state and haunt his body. In other words, those who drool while sleeping are considered unclean and are subject to be haunted by ghosts or to go insane.