Pot smokers more than double risk of dropping out of school

Youths who used cannabis daily before age 17 showed the worst effects in a new study. Photo / 123RF

Teen cannabis smokers are 60 per cent more likely to drop out of high school than their non-smoking peers, and are more likely to use other drugs and attempt suicide.

The latest Australian research has also found there is no "safe" level of adolescent cannabis use. There are poorer educational outcomes and increased risks even for those using the drug less than one a month.

Amid calls to legalise the supply of medicinal cannabis, the authors of the study, which is published in the Lancet, say the results are a timely reminder of the drug's harm.

"Policymakers need to be aware that the early use of cannabis is associated with a range of negative outcomes for young adults that affects their health, wellbeing and achievement," said lead researcher Dr Edmund Silins, of the University of NSW's National Drug and Alcohol Research Centre (NDARC).

"Any efforts to reform cannabis legislation should be carefully evaluated to ensure they reduce adolescent cannabis use and prevent potentially adverse effects on adolescent development."

Researchers compiled data from three large, long-running Australian and New Zealand studies to compare education and other outcomes for about 4000 young people up to the age of 30.

Youths who used cannabis daily before age 17 showed the worst effects: they were about 60 per cent more likely than a non-smoking peer to drop out of high school or not attain a university degree.

"The greater the frequency of cannabis use, the more likely young people were to experience these outcomes, with daily cannabis use showing the strongest effects," said co-author Dr Delyse Hutchinson, also of NDARC.

Negative outcomes were also evident for teenagers who smoked cannabis less than once a month. Dr Hutchinson said there was "no evidence for a safe level" of cannabis use.

An earlier study found about four per cent of Australian 14- to 19 year-olds used cannabis weekly, and one per cent used it daily.

A youth who smokes pot daily before age 17 is:

• 63 per cent less likely than non-smoking peers to finish high school

• 62 per cent less likely to complete a university degree

• 18 times more likely to later become dependent on cannabis

• 8 times more likely to go to use other drugs

• 7 times more likely to later attempt suicide.

- AAP