Are Australian cannabis users more likely to be diagnosed with or treated for mental illness, compared to those who do not use cannabis?

Australians (aged 18 years and older) who have used cannabis in the past 12 months are more likely to have been diagnosed with/treated for a mental illness (21%) in the past 12 months than those who have not used cannabis in the past 12 months (13%).

Source: Australian Institute of Health and Welfare (AIHW). 2013 National Drug Strategy Household Survey.