Michael Fletcher was last seen at his home at about 11am on Friday 10th October, Nottinghamshire Police said.
He does not have his medication with him and may be confused about his surroundings.
Police say they are increasingly concerned for his welfare and keen for Michael, or anyone who has seen him, to get in touch.
Michael is white, of a medium build, about 6ft 1ins tall, and has short grey unkempt hair.
He was wearing dark trousers, a grey jumper, a navy coat jacket and brown shoes when he went missing.
He has links to Nottingham and Derby and may have travelled to either city.
If you’ve seen Michael please call us on 101 or Crimestoppers on 0800 555 111.