Tolerance of cannabis is growing just as scientists show that it can cause insanity

 As long ago as 1896 these claims were made about inmates of mental hospitals in India that used cannabis - the first UK Royal Commission, the Indian Hemp Drugs commission looked into those claims and concluded that cannabis actually helped many and also that the mental health problems often led people to use cannabis to find relief, and cannabis was legal there in those days. There have been numerous other studies into cannabis and mental health and although there is some evidence that a small number of people with mental health problems get worse through uncontrolled consumption of cannabis with high THC and low CBD content, on the whole the reports failed to prove any detrimental effect to the vast majority of consumers.

In addition I would emphasize that even in cases where it may be true, that is no reason to punish either those people or those that benefit from cannabis consumption - it is a matter of health and should not be a mater of law. The criminalisation of millions of people that have done no harm cannot be justified because a minority may have suffered ill effects; otherwise alcohol would have been banned from non-medicinal production or supply many years ago, including home brewing.

Indian Hemp Drugs Commission

Tolerance of cannabis is growing just as scientists show that it can cause insanity 
The Independent, October 12 2021

Supporters of cannabis legalisation are like the tobacco companies denying the link between smoking and cancer