Sgt. Mike Crowder says Andreano Farinas admitted taking the drug Molly on Sunday and had a bad reaction.
He was still disoriented when he was noticed Monday by people at Crescent Bar near a boat ramp. He was OK and reunited with his family.
Crowder says Farinas doesn't exactly remember what happened over an 18-hour period.
He traveled about eight miles from the Paradiso Festival. He said he walked and swam around cliffs and crawled into a cave when it got dark.