From Rogschard's wiki
When consuming Alcohol, one level of drunkenness will be added to the player, and the total time till sober will increase.
- On the first level of drunkenness the player will gain +1 Instinct and their Wisdom will be halved rounded up.
- On every level of drunkenness after the first the player's Wisdom will be halved again rounded up.
Drunkenness is a good method on passing low Wisdom checks, like those during the Hornspore Cluster encounter.