Hussam Bashraheil was last seen in the Poplar area on Thursday, 14 January. The 21-year-old was reported missing in February.
Officers from the Central East Missing Persons Unit are carrying out enquiries and believe he could have travelled to the Theydon Bois area of Essex on Saturday, 30 January.
Hussam’s picture is a good representation of how he would look now, but he also may have now grown facial hair.
Detective Constable Amanda Lloyd, said: “Hussam’s family are understandably concerned about his disappearance, which is completely out of character.
“We are following a number of lines of enquiry and one hypothesis is that Hussam is sleeping rough or camping in a tent.”
Hussam is known to suffer with a number of mental health issues which can make him paranoid and behave in an erratic manner.
His sister wishes to give him a message: “Hussama I pray for your safety every day. I miss our jokes and I just need to know you’re ok.”
If anyone has seen or heard from Hussam, or if Hussam is reading this appeal, please contact the police on 101 and quote reference CAD 5397/13Apr. You can also report information anonymously to the Missing People charity on 180 000.