A new study has revealed Australians are the top cannabis smoking nation in the world, with a third of our all Aussies using the drug in their lifetime.
The Australian study also shows dope smokers have a 40 per cent increased risk of developing schizophrenia, with regular users also found to double their risk of getting the mental illness.
Lead researcher Dr Martin Cohen, a psychiatrist at the Hunter New England Mental Health Service says the evidence of links between cannabis use and mental illness is "stronger and clearer than ever".
"On the world stage, Australians excel in smoking cannabis, so there are very many people who fit into this category.
"In fact we're number one in the world.
"We know now more than ever that this bodes badly for our mental health."
The review, published in the latest Australian and New Zealand Journal of Psychiatry, calculates about 14 per cent of all cases of psychosis would never have occurred if the patient didn't pick up a joint.
The risk is also higher for people who start smoking young and those who use heavily.
A 1998 national drug survey of 14 to 19 year olds showed 20 per cent had smoked in the last week, and 20 per cent of these took their first puff before they turned 12.
"These teenagers are the ones we really need to worry about because their use is changing a developing brain," Dr Cohen said.
