Australian PM links cannabis use to mental illness

February 13, 2006 Australian Prime Minister John Howard has linked cannabis use to mental illness, and called for state governments to take a tougher line on the drug. Speaking at a meeting of Federal, state and territory leaders, Mr Howard said that fighting drug abuse would be a significant element of the new mental health strategy.

At a COAG press conference on Friday, Mr Howard explicitly stated that there was a relationship between cannabis use and mental illness. "We need, as part of the campaign on mental health, to address cannabis and amphetamine abuse which is a key, but not of course the only ingredient in the problem," he said.

Mr Howard has also said that in the past Australians have not taken the problem seriously. "At least a generation of Australians were too passive about the consequences of illicit drug use," he said.

South Australia's Director of Public Prosecutions, Stephen Pallaras QC, called today for courts to be tougher on cannabis related crime, because of the harm to the mental health of cannabis users. "I have heard the research on the link between mental illness and cannabis and it concerns me greatly," he said. "It may be time to reassess the way the court approaches sentencing in light of research on cannabis. We are waiting for the right case to bring before the court of appeal."

South Australia has separate penalties for cannabis possession in public and in private. In South Australia possession of up to 20 cannabis plants for personal use is punishable by a AU$500 fine.

Professor George Patton, of the Centre for Adolescent Health in Melbourne, also made the link between the drug and mental illness, suggesting that there was evidence of a "predictive" link between cannabis use and the development of illnesses such as schizophrenia. "People presenting with schizophrenia for the first time, depression and anxiety, often have frequent cannabis use (and) there's increasing evidence cannabis use predicts the development of schizophrenia and other psychotic illness," he said.

"The big difference from 20 or 30 years ago is there were fewer people using cannabis then. What we're learning now is that cannabis these days is a potent drug with powerful side effects."

Dan Lubman, consultant psychiatrist at Orygen Youth Health, warned that the relationship was quite complicated, and argued that it was difficult to draw clear conclusions.

"A high percentage of the population we treat are cannabis users with mental health problems, but just because you use cannabis doesn't mean you'll develop psychosis," he said. "It's a complicated relationship and that's why we need to be very clever about how we approach this issue."

The Mental Health Council of Australia has warned the government of over-estimating the role of cannabis in mental health. John Mendozza told ABC "I don't think we should overstate the role of cannabis in the nation's mental health crisis. It is a factor, but it is not the reason that we now face a mental health crisis."