A Silver Alert has been issued for a Green Bay man who suffers from dementia and is no longer taking his medications, according to authorities.Matthew Zahn, 65, was last seen in the 600 block of N. Maple Avenue in Green Bay. Aut horities said Zahn suffers from dementia and has become paranoid, believing people are after him. The last time anyone heard from Zahn was by phone on Monday.Zahn is believed to be on foot, and authorities said he walks slowly. He is 5 feet 11 inches tall, weighs about 180 pounds, has blue eyes, brown shoulder-length hair, a mustache and possible scruffy facial hair.Anyone with information is asked to contact the Green Bay Police Department at 920-448-3200. ...read more read less