Thomas Harris, 31, was last heard from Friday after he sent a text message to a family member.
Authorities say because of his medical status, there is a real concern for his welfare.
Harris from the unit block of Windsor Circle is described as a black male, 6'1'', 210 pounds, with brown hair and brown eyes.
He is known to have family in several surrounding states and could possibly be operating a white Chevrolet Trailblazer.
Anyone with information regarding his whereabouts, please call the New Castle County Police Department at (302) 573-2800
