Police are searching for Francesca Pirrone, who is missing from Hove.
The 43-year-old, who is a patient at Mill View Hospital, absconded from staff while walking to the local shops around 6.30pm on Wednesday 19 August.
She is vulnerable and is not believed to be in possession of a mobile phone. She was last seen heading in the direction of Portslade, and may have taken public transport.
Francesca is white, about 5’8”, of medium build, with short blonde hair. She was last seen wearing a long grey jumper, blue jeans and black trainers.
Anyone who sees Francesca is urged to call 999, quoting serial 1238 of 19/08.