No evidence cannabis reduces long-term illicit opioids use, study finds

Lead author says study led by University of Sydney is longest ever to have looked at relationship between the two drugs

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Cannabis should not be considered an effective long-term strategy for reducing opioid use, according to a new study released amid the global shift towards cannabis legalisation.

A study led by the University of Sydney, published on Wednesday in the American Journal of Psychiatry, followed 615 people with heroin dependence, many of whom also used cannabis, over 20 years.

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