Smoking cannabis ‘isn’t as bad for teenagers as everyone thought’

For years, anti-drug campaigners have cited studies showing that cannabis causes irreparable harm to teenage brains – as evidence that the drug should be banned.

But the studies actually ‘overstated’ the damaging effects of the drug – and a new review found that cannabis has little negative effect after three days abstinence.

Researchers from the University of Pennsylvania analysed 60 previous studies to analyse the drug’s effects on memory, learning and language.

The researchers did not investigate links between cannabis and psychosis.

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The researchers found that studies where the teenagers had abstained from the drug for 72 hours showed almost no ill effects.

The researchers write, ‘In light of the changing perceptions of cannabis use and an evolving policy landscape surrounding cannabis, understanding the potential risks of cannabis use for mental health and brain functioning is of paramount importance

‘These results indicate that previous studies of cannabis in youth may have overstated the magnitude and persistence of cognitive deficits associated with use.’

‘Reported deficits may reflect residual effects from acute use or withdrawal.’