PCH was shut down between Trancas Canyon Road and Morning View Drive, the Sheriff's Department tweeted shortly before 10 a.m.
The closure was "due to a possibly suicidal person in a RV," the tweet said. The individual was armed with a knife, a sheriff's spokesperson told ABC7.
Shortly before 12:30 p.m., authorities said the incident had been resolved without incident and PCH was reopened in both directions.
"With the assistance of LASD's Mental Evaluation Team (MET), they were able to talk to the person and get him the help he needed," the Sheriff's Department said on Twitter.