Police are very concerned for the welfare of 26-year-old Jack Davies from Seaford.
Jack is believed to require medical treatment and officers are keen to locate him promptly to ensure his wellbeing.
He is described as white, of a slim build with brown hair and brown eyes. It is thought he may be in the Brighton or Seaford areas.
Anyone who has seen Jack or who has information on his whereabouts is urged to report online or call 101.