A London-based human rights group has filed a motion in a U.S. court seeking the release of the last British resident in Guantanamo Bay.
The results of an independent medical evaluation of Shaker Aamer, organised by campaign group Reprieve, declared that the father of four has been diagnosed with post-traumatic stress disorder.
Aamer's lawyers will use the medical report to seek his release under the Geneva Convention.
During a forensic examination that lasted 25 hours, Aamer spoke of severe torture and harsh conditions, which may have led to physical and psychological harm.
The medical report added that Aamer suffered from debilitating headaches, asthma, and chronic urinary retention.
Speaking from inside the detention centre, Aamer said he was focussing on returning to his family. Aamer has indefinite permission to live in the U.K. because his wife is a British national.
He said he had "faith in my Lord... I do not believe I will die here. I must survive for my family. But it is hard, it is hard."
He also told ITV News that he believes he will released this year.
Aamer has been detained for 12 years without charge and has reportedly been cleared for release to Saudi Arabia, where he was born.
His lawyers argue, however, that his psychiatric symptoms would deteriorate if repatriated to his country of birth.
Dr. Emily Keram, who assessed Aamer at the detention centre, said, "The length, uncertainty, and stress of Mr. Aamer's confinement has caused significant disruptions in his ... ability to function. He is profoundly aware of what he has lost."
She added, "M.r Aamer requires psychiatric treatment, as well as reintegration into his family and society and minimisation of his re-exposure to trauma and reminders of trauma."
Clive Stafford Smith, one of Aamer's lawyers, has sent a copy of the medical report to Foreign Secretary William Hague.
A Foreign Office spokesman said: "Mr. Aamer's case remains a high priority for the U.K. government and we continue to make clear to the U.S. that we want him released and returned to the U.K. as a matter of urgency."