There has been a significant increase in the number of Americans using cannabis, rising from 21.9m in 2002 to 31.9m in 2014. The number of regular users doubled over the same period to 8.4m. This coincides with an increasingly liberal approach to cannabis regulation in several US states.
The authors of a new study, published in The Lancet Psychiatry, also found that people perceived cannabis to be less harmful. This perception seems justified as problems related to cannabis use, such as dependency, remained stable during the study period.
These findings are not what you would expect when cannabis use becomes more popular and is thought to be increasingly potent. This study also contradicts another study, using data over the same period, which found that disorders associated with cannabis use have doubled. So which one should we believe?
The study in The Lancet Psychiatry is problematic as it doesn’t include some of the most