Two Western State Hospital staff members thought they were escorting eight patients from a fenced activity area on the campus Monday.
When they reached their destination about 1:45 p.m., there were only seven patients, Lakewood police said.
The 31-year-old patient who escaped was taken into custody without incident at 3:05 p.m. and returned to the mental hospital, police spokesman Lt. Chris Lawler said in a statement.
Kathy Spears, a spokeswoman for the Department of Social and Health Services, said the patient is believed to have escaped through an unlocked door in the activity area.
The patient was civilly committed to Western State on March 1 from Cowlitz County and is considered gravely disabled and a threat to himself and others, Lawler wrote.
He also is on active supervision from the state Department of Corrections.
Hospital security began searching for the patient and received reports he was near the Steilacoom library. He eventually was seen along Steilacoom-DuPont Road, where he was taken into custody.
“I thank the Lakewood Police Department and the hospital’s fast-acting security staff for quick action in locating and returning the patient to the hospital,” Cheryl Strange, the hospital CEO, said in a news release.