Northamptonshire Police have appealed for people to call 999 if they spot a high risk missing man believed to be in the area of Irthlingborough,
Officers said Reuben Bilsby should not be approached.
They did not release any more reasons as to why they believed him to be high risk.
They added that they were concerned for his welfare, and anyone who saw him should phone the emergency police number immediately.
Reuben was last seen wearing blue jeans, a blue denim jacket and blue boots.