MANY young ice addicts have shrunken brains the size of people aged in their 70s and giving up drugs is unlikely to reverse the damage, research has found.

Staff at the University of Western Australia used magnetic resonance imaging to scan the brains of addicts who use about one gram of crystal methamphetamine a week.

They found a 28-year-old man who had been injecting ice twice a week had a brain about 15 per cent smaller than expected, while a 38-year-old who had been using ice for 10 years had severe scarring on his brain that could not be attributed to any other cause.