Children as young as eight are being given cannabis as part of a medical trial to test the drug's benefits on treating behavioural issues.

The Murdoch Children's Research Institute has been undertaking the trial at its Melbourne base since the beginning of the year.

The study is focused, in particular, on children living with an intellectual disability and who are prone to aggression and self-harm, The Herald Sun reported.

If it is successful, it could provide an alternative medication to antidepressants and anti-psychotic drugs, which come with nasty side effects.

Children as young as eight are being given cannabis as part of a medical trial to test the drug's benefits on treating behavioural issues (stock image)

The Murdoch Children's Research Institute (pictured) has been undertaking the trial at its Melbourne base since the beginning of the year

Up to 25,000 young people living with a disability stand in line to benefit if the results prove promising.

'It is hell for these kids a lot of the time — they are really aggressive, damaging property, injuring themselves, injuring other people,' lead researcher associate professor Daryl Efron said.

A handful of children aged between eight and 16, who live with intellectual disabilities like autism, are part of the pilot study.

The cannabis used in the trial is sourced from Canada and only contains its cannabidiol element - an active ingredient that provides the therapeutic benefits without the high commonly associated with the drug.

For eight-weeks, the children drink two teaspoons of peppermint-flavoured mixture every day.

Half take the medicine, while the other half are on a placebo.

Dr Efron said the early signs were already pointing to a positive outcome.

He said the children had responded well to the medication and the positive impact was even noticeable in the parents.

'I have no doubt medical cannabis has a wide range of application in kids, and particularly for kids with behavioural problems.

'But we really need to understand which kids it is going to be helpful for, which form of medical cannabis, and which particular symptoms it is going to help with — so we need to do proper studies.'

Heather Renton's daughter Rebecca is one of the children who is part of the trial.

She said she welcomed any alternative medication that might help her 12-year-old, especially ones that didn't come with side effects.

Ms Harvey said her daughter was prone to meltdowns and the aggressive behaviour made it difficult to cope.