A former detainee at Perth's Banksia Hill juvenile prison has described being brutalised by guards, denied phone calls and left to sleep naked on a concrete floor.
The Noongar man, known only as Nathan to protect his identity, has told the disability royal commission he was left "broken" by his time inside Western Australia's only youth detention centre.
Nathan, who grew up in poverty and neglect, had 10 stints at Banksia Hill between 2012 and 2017.
He described being bashed after he vomited in a prison van returning from hospital when aged 12 or 13.
"When we got to Banksia, the guards opened the (van) doors and as soon as I stepped out, the officer hit me and winded me," Nathan said in a statement read on his behalf to the commission.
"He pushed me into the sand and called me a 'little black dog.'
"He punched me in the back, 15 or 16 times. I was calling for help so they put a bag on my head.
"They dragged me to the multi-purpose cells ... I stayed in there for about a week."
Nathan described those cells as "dirty and disgusting" with the lights kept on at all times, preventing him from sleeping.
He claimed he was sometimes only let out for 20 minutes a day and denied phone calls.
After being involved in a riot in 2017, Nathan said he had to sleep naked on concrete because he was not given a mattress and had his clothes confiscated so he couldn't attempt self-harm.
He alleged he was bashed by a group of officers while handcuffed in his cell the following day.
The commission heard Nathan had grown up in poverty and started using methamphetamine aged 13 or 14.
Having been diagnosed with depression, anxiety and ADHD, he described being cycled between different psychiatrists at Banksia Hill who frequently changed his medication.
His loved ones were allegedly not told when he made the first of several self-harm attempts.
Nathan, who is now aged 23 and in an adult prison, said he was left broken by repeated stints in isolation as a teenager.
"Banksia me took to a dark place and ruined my life," he said.
"I no longer feel like I can have relationships with anyone. I feel stuck and like I can't trust anyone anymore.
"I had never tried to self-harm before I went to Banksia. What happened at Banksia made me feel so bad that I wanted to kill myself."
An independent inspector this year found some boys at Banksia Hill had recently spent as little as one hour a day outside their cells, in violation of their human rights.
A group of boys were moved in July to a standalone unit at the Casuarina maximum-security adult prison after they self-harmed and destroyed cells at the juvenile facility.
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