Police are searching for Daniel Rawlins, who is missing from Littlehampton.
The 44-year-old was last spoken to around 1pm today, and police are concerned for his welfare due to his vulnerability.
He is described as white, 5ft 8in, of heavy build, with brown hair and blue eyes.
He has a marlin tattoo on the left side of his chest and a large tribal tattoo covering his back, police said.
Anyone who sees Daniel or knows where he could be is asked to report it online or call 101 quoting serial 610 of 14/05.