Oscar Pistorius sits in the dock on Monday. Picture: Chris Collingridge

Pretoria - An analysis of Oscar Pistorius's psychological state has prompted the question if an anxiety disorder led to his behaviour the night he shot and killed Reeva Steenkamp.

The second witness called to the stand in the High Court in Pretoria High on Monday was Professor Merryll Vorster, a specialist forensic psychiatrist.

She compiled a report on her psychological evaluation of Pistorius.

Vorster said she had interviewed the athlete, as well as his coach, family and friends to determine his mental state.

She mentioned that Pistorius's condition and amputation of both legs took place before he was able to verbalise, thus unable to understand why he was in hospital.

Vorster said he was always encouraged to behave and appear as normal, meaning he was never able to allow himself to be seen as being disabled.

Over time, she said this could result in increasing levels of anxiety as he struggled to maintain normality.

Pistorius described his mother as very loving, and at the age of six, she and his father divorced, resulting in “drastic changes”.

Both Pistorius and his siblings, Aimee and Carl, described their father as an absent parent, and said their mother occasionally had problems with alcohol. Their mother had slept with a firearm under her pillow, and her lack of ability to relieve her children's anxiety meant she added to it.

Carl was often tasked with looking after his siblings, and his paternal grandmother helped them out financially.

Pistorius was mocked at times in primary school for his prosthetics, and his brother occasionally had to step in to help.

Vorster said Pistorius often concealed his disability. At age 14, Pistorius moved to Pretoria to attend high school, and because of problems with his father became a weekly boarder. He would mostly visit his mother and grandmother on the weekends.

Pistorius told Vorster he was sociable and athletic, with no problems with his academic performance.

The death of his mother increased his anxiety, after losing his emotional crutch. From then he had no primary adult attachment figure.

At 16, Pistorius began running competitively, and in grade 11 was earning money and becoming financially independent.

At this point, he had few emotional ties, only maintaining relations with his direct family, excluding his father who he stopped speaking to at age 21.

Vorster said Pistorius's anxiety over crime in South Africa led to him purchasing a gun, as well as the security measures he had installed at his home.

Vorster described Pistorius as dedicated to his athletic schedule, usually punctual and generally self-sufficient.

The psychiatrist said Pistorius had an anxiety disorder, and lived in a very strict, controlled environment to alleviate his worry.

As he became more famous, he had to prepare more and more to avoid public embarrassment.

She said many people suffering with anxiety issues use these organisational methods to cope.

Pistorius's past medical history was then detailed by Vorster.

Besides his amputations, he suffered encephalitus as a child leading to chronic headaches. A boating accident in 2009 injured him badly. Vorster said Pistorius's relatives also suffered from anxiety disorders.

“Anxiety disorders do have genetic predisposition,” said Vorster.

She said his stumps had left him with a damaged self-image, which was why he concealed his disability. When he became sexually active, he felt even more anxious about his disability, according to the professor.

He felt the demands and expectations continued to build his anxiety, and the effort to control it increased exponentially as he became known across the globe.

Pistorius told Vorster he felt concerned about crime, especially the possibility it could affect his siblings.

“With increased levels of anxiety, you perceive your surroundings as being threatening, even when they aren't,” said Vorster.

He said he was worried about being followed and potential attacks, and moved into a closed estate for extra security. Pistorius also claimed to have sleep disturbances and would often wake up to any and all noises in his home. Vorster described the athlete as “hypervigilant”, a feature of his anxiety disorder.

He would often invite friends to spend time with him at his home to combat his loneliness. Pistorius was described as a distrustful and guarded person.

Vorster said when he thought an intruder had broken into his home the night he shot Reeva Steenkamp this had led to increasing levels of anxiety.

She described Pistorius's retching and crying during his trial and cross-examination as “genuine”, as he didn't display any physical features that would emerge if he were faking such emotions.

When she interviewed him, she mentioned that Pistorius's mood was markedly depressed, with minimal expression in his face and voice. She said he seemed nervous, and perspired during the interview.

During consultations she did not, however, notice any memory or concentration problems, other features of depression.

She said that without his prosthetic legs, his physical vulnerability was apparent - and this meant he was more anxious without them.

Vorster also diagnosed Pistorius with depression caused directly by the shooting incident.

Pistorius was also wary of former soccer player, Mark Batchelor, after an “incident” in 2012. Pistorius thought that the player and his friends were an ongoing physical threat.

In her opinion, Vorster believed Pistorius was more likely to engage in a fight response than a flight response because of limited mobility.

During the time of the shooting, Pistorius's thoughts of an intruder breaking into his home, his anxiety and his vulnerability on his stumps were at the forefront of his mind.

She added that the athlete felt guilty about Steenkamp's death, and his depression was caused by this.

Nel began his cross-examination by asking if Pistorius's anxiety disorder diminished his responsibility on the night of the shooting.

She said no, but that Pistorius's reaction to situations would be different because of his disability and disorder.

Nel asked why - if Pistorius's mental issues didn't directly affect his behaviour - there was a point in providing such psychological evidence to the court. “His reaction is not that of a normal able-bodied person without an anxiety disorder,” said Vorster.

But the psychiatrist said that the disorder was not a mental illness, as considered in the Criminal Procedure Act, which meant Pistorius did not have to come under observation for fitness to stand trial.

Nel said that if his disorder was linked to the case, he should have been referred for observation, but Vorster disagreed.

Nel asked if severe general anxiety disorder could affect a person's judgment or capacity to make normal choices. She said if someone's anxiety turned to paranoia, then it ultimately could, but that many people suffered from the disorder without losing touch with morality.

Nel indicated that he may have to apply for Pistorius to be referred for evaluation.

He then asked for an hour to analyse Vorster's report, which he'd only received on Monday morning.

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The Star