He said he remembered going to the female toilet to take drugs.
"It's difficult to say what happened," Ninow said breaking down in tears.
"This is something I have to live with ... I made a mistake. I intentionally did those things to her. I knew what I was doing. I was in a different mind state. There was no emotion attached," he said.
Ninow told the court that he started using drugs at the age of 13. He was introduced to "chemical" drugs by his mother. "The first time I consumed chemicals was with my mother."
He said his mother had always been on drugs.
He described his relationship with his mother, who is 37 years old, as that of brother and sister.
He claimed drugs gave him a different personality and that they were a coping mechanism for him.
"It's always been a coping mechanism - all my life."
Ninow told the court that he was using drugs in prison because "drugs are everywhere in prison".
The trial continues.