Oscar Pistorius is suffering from depression, a South African court heard Monday, as the Paralympic athlete faced a return to jail for murdering his girlfriend Reeva Steenkamp three years ago. The double-amputee killed Steenkamp, a model and law graduate, in the early hours of Valentine's Day in 2013, saying he mistook her for an intruder when he fired four times through the door of his bedroom toilet. "He displayed signs and reported symptoms of post-traumatic stress disorder, anxiety disorder and depressive disorder," psychologist Jonathan Scholtz for the defence said, after recent interviews with Pistorius. "Currently he is not able to testify. His condition is severe."