Psychiatrists Hugh Richards from Britain and D L Crisson from the US warned on Tuesday that if al-Hajj remained in the camp, his life could be in danger.
Clive Stafford-Smith, al Hajj's lawyer, told Al Jazeera: "I'm incredibly worried about him.
"Last time I saw him ... he was talking about death."
Al-Hajj, originally from Sudan, was arrested in Pakistan in December 2001 on the Afghanistan-Pakistan border by Pakistani intelligence and was handed to the US military in January 2002.
The cameraman is one of about 20 prisoners in Guantanamo Bay who have carried out a hunger strike in protest at their imprisonment and treatment at the US detention centre in Cuba.
In July, al-Hajj had reportedly lost 18kg in weight since he began the hunger strike, according to notes from a meeting with his lawyer.
Stafford-Smith said the US military was behaving shamefully by force-feeding hunger strikers.
Al-Hajj has also complained that hunger strikers at Guantanamo were stripped of all their personal items except their clothes and had only a thin mat on which to sleep.
The two psychiatrists said in their letter that al-Hajj was in a constant state of fear and anxiety and felt that he was being pursued and could be killed.
The two said al-Hajj needed immediate treatment from specialised doctors to alleviate his condition.
The cameraman, who has been accused by the US of having links to al-Qaeda, could be released if Khartoum guarantees that he remains in Sudan.
However, negotiations over his release stalled in August and Stafford-Smith urged the authorities in Qatar, where Al Jazeera is based, to intervene on behalf of their employee.