Consultant pharmacist Manya Angley told the commission that she strongly believed psychotropics were both over-used and misused in Australia.

She said unless such drugs, which could include anti-psychotics, were prescribed as a last resort, then the person had been denied their right to proper intervention and care.

"I also think if they are prescribed medicines that don't have evidence for benefit and they are solely being prescribed because of their tranquilising effects or their sedative effects, rather than addressing the underlying problems, then that is abuse," she said in video evidence from Adelaide on Tuesday.

"It's neglecting to give them the proper care that they are entitled to as human beings."

As part of her role, Dr Angley conducts home medicine reviews, checking on the suitability of medication prescribed for an individual patient.

She detailed one of those reviews where a young man with autism and bipolar disorder had been prescribed two anti-psychotic drugs on an ongoing basis.

One of those was prescribed at twice the maximum dose and the second had no evidence of assisting with either of his conditions.

He was also prescribed a third antipsychotic drug on an as needs basis.

Dr Angley said despite all this support workers reported that his behaviours were worsening.

"The issue here was that he was prescribed two regular anti-psychotics, a third one on a when-required basis and none of it was working," she said.

In other evidence, the commission was told medical professionals should get mandatory training in dealing with people with intellectual disabilities, particularly in the use of psychotropic drugs.

Special education teacher Paula McGowan recounted the story of her son Oliver, who had a mild intellectual disability from birth.

Oliver died in 2016 of a combination of pneumonia and hypoxic brain injury after having a severe reaction to a psychotropic drug called olanzapine.

Ms McGowan said the 18-year-old had been given the drug while having a seizure because of behaviour that was perceived as challenging.

But she said she believed his behaviour was the very same that any other person, who was rightly frightened and anxious, would experience while in seizure.

"We believe that if Oliver had not have had the labels of autism and intellectual disability attached to him he would absolutely have not have been prescribed psychotropic medications," Ms McGowan said.

Ms McGowan has since moved to Australia with her husband, and said she believed there might be similar issues here in relation to the over-medication and premature death of people with a disability amid a lack of training.

"I feel strongly it is wrong that we expect our doctors, nurses, social workers to suddenly know how to help a person with intellectual disability when they are in a sensory crisis," she said.

"We wouldn't expect them to go out and fix a car if they've not been given mechanical training.

"So why do we expect them to suddenly know how to treat and support our most vulnerable people?

"They simply don't have the skills to do so right now and it is affecting lives, it costs lives and it costs the quality of life."

The commission is examining the abuse and neglect of people with a disability, with its latest hearing in Sydney focused on the use of psychotropic medication to deal with challenging behaviour.

Australian Associated Press