A family are concerned about their brother who has been missing since Thursday without vital medication.
Taha Deria, 32, disappeared from his home in Penarth Road, Cardiff , without a mobile phone, with no money in his pockets and without the medication he needs on a daily basis.
His family said Taha, who doesn't work, needs help to live his daily life after being discharged from University Hospital Llandough in May. They said he has never been missing before.
His sister Hodan, 28, said: "He has severe mental health problems. He is unable to make decisions for himself. He is unable to buy clothes for himself or use cash points."
She said: "We are really trying to stress just how vulnerable he is. We are convinced he is dead."
Taha is thought to have been missing from the family home since 11.30pm on Thursday, June 6.
He is of big build, around 5'11" tall and with a rough beard. He was wearing Adidas Sliders shoes, black jogging bottoms and a T-shirt when he went missing.
His brother Tahir, 26, said: "I don't think he's alive. I know how dependent he is on his family.
"When I take him out and drive him around he would rather stay at home."
He added: "My fear is that he could have stumbled into the River Taff and fallen into it."
Police echoed the family's appeal for information. A spokesman said Taha was known to frequent the Grangetown area of Cardiff.
Anyone with information should call police on 101 quoting reference number 1900204162
