Cannabis and psychosis: new research highlights the risks

Cannabis has become increasingly normalised in Australia — both recreationally and as a medicine. But important new research is adding to the evidence about its relationship with psychosis.

ASoP member Prof. Matthew Large and colleagues at UNSW Medicine & Health analysed 149 studies involving more than 70,000 people and found cannabis use was associated with an earlier onset of psychosis. The effect became more pronounced with age, suggesting cumulative exposure may progressively lower the threshold for psychosis.

The research was featured in The Sydney Morning Herald, The Age and Brisbane Times, and across Nine newspapers nationally.

ASoP CEO Dr Pramudie Gunaratne said:

“Cannabis has become increasingly normalised as both a recreational drug and a medicine. This study is an important reminder that normalisation doesn't make it harmless.”

The findings are particularly important given the rapid growth of medicinal cannabis in Australia.

“The growth of medicinal cannabis has been incredibly rapid, but our understanding and communication of the psychiatric risks hasn't kept pace.”

As cannabis becomes more accessible, regulation and clinical practice need to keep pace with the evidence. This means appropriate prescribing safeguards, careful consideration of psychiatric risk, meaningful informed consent and clear, evidence-based information — without judgement or stigma.

The story also shares the experience of Andrew Leunig and his son, Patrick, bringing a deeply human dimension to the research. Behind the statistics are real people and families, and the consequences of severe mental illness can be profound.

Read the full article by Rachel Rasker: here