The judge in the Oscar Pistorius trial has ordered him to start daily tests on Monday to assess his mental state when he killed his girlfriend.
Judge Thokozile Masipa told the South African athlete to attend Weskoppies psychiatric hospital in Pretoria as an outpatient for a month.
It comes after a defence witness said the double amputee was suffering from Generalised Anxiety Disorder (Gad).
Mr Pistorius denies intentionally killing his girlfriend Reeva Steenkamp.
He says he accidentally shot her through the toilet door on Valentine’s Day last year in a state of panic, mistaking the 29-year-old model and law graduate for an intruder.
The prosecution had argued the tests were essential after forensic psychiatrist Merryll Vorster told the court in Pretoria the double amputee was “a danger to society”.
But the defence vigorously opposed the move.
Judge Masipa said on Tuesday that four appointed psychiatrists would “inquire into whether the accused by reason of mental illness or mental defect was at the time of the commission of the offence criminally responsible for the offence as charged.”
She said the team would decide whether he was “capable of appreciating the wrongfulness of his act”.
Court proceedings were adjourned until 30 June.
Legal experts say that the case may well hinge on the judge’s understanding of the athlete’s state of mind when he pulled the trigger.
They say the prosecution is keen to show that the defence keeps changing its reasons why Mr Pistorius fired his gun – from putative self-defence, to accidental shooting, and now to something linked to his anxiety disorder.
Prosecution lawyer Gerrie Nel has also said he is trying to prevent mental illness being used as an argument in any future appeal.
Last week Judge Masipa said that the criminal code stipulates that if an accused person is alleged not to be criminally responsible or is alleged to be mentally ill, he should be evaluated.
Weskoppies psychiatric hospital was founded in 1892 and is a 1,400-bed hospital affiliated to the University of Pretoria.
There are no juries at trials in South Africa, so the athlete’s fate will ultimately be decided by the judge, assisted by two assessors.
If found guilty of murder, Mr Pistorius could face life imprisonment. If he is acquitted of that charge, the court will consider an alternative charge of culpable homicide, for which he could receive about 15 years in prison.