sīdat - failing; cittam - the higher faculties of consciousness; vilīyeta - become dissolved; cetasaḥ - awareness; grahaṇe - in controlling; akṣamam - incapable; manaḥ - the mind; naṣṭam - ruined; tamaḥ - ignorance; glāniḥ - depression; tamaḥ - the mode of ignorance; tat - that; upadhāraya - you should understand.

When one’s higher awareness fails and finally disappears and one is thus unable to concentrate his attention, his mind is ruined and manifests ignorance and depression. You should understand this situation to be the predominance of the mode of ignorance.