The University of New South Wales has published the results of a study which they claim provides the first conclusive evidence that cannabis use accelerates the onset of mental health illness such as schizopherenias and other psychotic illnesses.

The study analysed results from 20,000 patients with psychotic illnesses and determined through statistical analysis that patients that used cannabis presented earlier symptoms of psychotic illness, and that this early onset of symptoms cannot be explained by other factors.

Dr Matthew Large from the University of New South Wales said the "results of this study are conclusive and clarify previously conflicting evidence of a relationship between cannabis use and the earlier onset of a psychotic illness, with evidence supporting the theory that cannabis use plays a causal role in the development of psychosis in some patients."

"The results of this study confirm the need for an ongoing public health warning about the potentially harmful effects of cannabis."