Samantha Taylor: Pistorius is emotionally unstable

The athlete's ex-girlfriend & her mother have described his extreme state of emotions while they knew him.

Paralympian Oscar Pistorius reacts as judgment is being handed down in his murder trial at the High Court in Pretoria on Friday, 12 September 2014. Picture: Pool.

JOHANNESBURG - Oscar Pistorius's ex-girlfriend Samantha Taylor has described the Olympic athlete's extreme emotional ups and downs over their 18-month relationship.

Taylor has opened up about her relationship with the blade runner, after he was convicted on Friday of culpable homicide and the negligent handling of a firearm.

The High Court in Pretoria accepted that he shot his girlfriend Reeva Steenkamp, believing she was an intruder, but found he was negligent.

Steenkamp was shot four times in Pistorius's home on Valentine's Day 2013.

Taylor says Pistorius was possessive and harassed her family and friends to get information about her.

"He was phoning my sister probably 10 or 20 times a day. He was phoning my mother in the middle of the night. He was checking up on me. He was asking my friends where I was and who I'm with."

Taylor's mother Trish says the athlete was emotionally unstable.

"He would cry for like a week and then out of the blue when things went well he would go on an absolute high. And then suddenly he'd be with women, drinking and fast cars."

Pistorius testified that he's been put on antidepressants since the shooting incident.

Taylor has also described the athlete's emotional breakdown during the 2012 London Olympics, which led to a fellow athlete moving out the room they shared.

She says Paralympic athlete Arnu Fourie moved out of the room he shared with Pistorius because of the fights he was having with her at the time.

"Arnu did move out because we were fighting on the phone all the time. There was a lot of screaming and crying and shouting and making up; so it was very back and forth."

Trish says the blade runner was also calling her.

"I thought he was going to commit suicide when he was away so often I would keep him on the phone until he stopped crying or he calmed down."

Fourie distanced himself from the incident but did not outright deny that it happened.

Meanwhile, Pistorius's agent has dismissed reports that his client is planning to write a book, as reported in a British newspaper at the weekend.

Peet Van Zyl has told Eyewitness News Pistorius has no plans to write a book, however he believes that his client may consider doing so once his trial and legal woes are over.

He has however dismissed reports that he has had such a discussion with the athlete and that it was even a consideration.

If the athlete is handed a custodial sentence or even community service, such plans may have to be scrapped.

Section 123 of the Correctional Services Act states no inmate or person subject to community corrections may derive profit from any published account of an offence the person was sentenced for.

Sentencing procedures have been set down for 13 October.

For more on the trial, click here.