Oscar Pistorius's anxiety disorder has reportedly caused worry among a number of families who are concerned that their relatives could become violent.

The Paralympic champion is undergoing testing at Weskoppies psychiatric hospital in Pretoria until the end of June.

The judge in the double amputee's murder trial ordered Pistorius to receive mental evaluation after Dr Merryl Vorster told the High Court last month that the athlete has suffered from an anxiety disorder since childhood.

The 27-year-old is accused of murdering his girlfriend Reeva Steenkamp, whom he shot dead through a bathroom door at his home in Pretoria on Valentine's Day last year.

According to The Mirror, the South African Depression and Anxiety Group have been contacted by families who are worried that the 'Oscar sickness' could make their relatives violent.

Director of the group Cassey Chambers is quoted as saying: "Many people have become nervous about telling others that they have GAD in case people also start to think that they are dangerous or violent.

"I don't think GAD had gone unnoticed before the trial. It's always been around, but I think because the trial is so high profile it's a very hot topic."

Pistorius denies murder by maintaining that he mistook Steenkamp for an intruder when he fired the fatal shots.