UPDATE: Louisha Mitchell returned home safe and well the day after a public appeal for help to find her was made.
A teenager from Portslade has been missing since the weekend, Sussex Police said.
The force said: “Louisha Mitchell has been missing from her home in Portslade since Saturday afternoon and there are concerns for her welfare.
“Louisha is 19 but has learning difficulties that lead to her presenting as considerably younger.
“She was last seen around 4pm on Saturday.
“She is of Caribbean appearance, 5ft 7in, very slim, with long dark hair and wears a nose ring.
“Anyone who knows of her whereabouts is asked to report online or call 101 quoting serial 522 of 16/12.”