New data presented at this year's International Early Psychosis Association (IEPA) meeting in Milan, Italy (20-22 October) adds to accumulating evidence that high-potency cannabis in associated with an increased risk of users becoming dependent on cannabis. The analysis is by Dr Tom Freeman at University College London, UK.

Estimates suggest around 182 million people worldwide use cannabis each year, a number that could rise as legalisation of recreational use and/or medical use increases. Roughly 9% of people who try cannabis will become dependent on it at some point in their lifetime. People who are dependent on cannabis are often unable to cut down or quit, despite experiencing persistent negative effects from the drug.

Some people are more vulnerable to the harmful effects of cannabis than others.