A severely disabled man said he is too scared to leave home after he was dragged into an alleyway, punched in the head and robbed in Kent.
Bradley Hannan, 29, from Chatham, who has suffered three brain tumours and weighs just six stone, was attacked as he waited for a bus in Luton Road.
His mobile phone and wallet were stolen during the incident, just after 15:30 GMT on Wednesday.
His parents appealed for anyone with information to come forward.
Mr Hannan was set upon as he waited for a bus home after volunteering at the Medway Maritime Hospital.
"I tried to walk off... he pinned me down, took my wallet out of the back pocket, hit me round the head and then took my phone out of my front pocket and just ran off," he said.
His father, Simon Hannan, added: "He can't defend himself. Someone's picked on a very vulnerable person. Despicable."
Chantal Hannan, his mother, said they had always brought him up to be very independent and she was concerned the attack had shaken his confidence.
The suspect, who ran away towards Constitution Road, is described as a man with tanned skin, aged between 20 and 30, of medium build. He was about 5ft 6in (1.6m) tall, with short black hair.
He was wearing a black jacket and dark blue jeans.
Kent Police said it is investigating the incident.