I can speak on why Sweden went from tolerant to totalitarian on the drug policy. I think this is where we have went totalitarian the most as well. In the 1960:ies when drug use started to spread out and be more well known the public as well as politicians went the opposite way from now. The legislation movement was much stronger. In the late 60:ies drug addicts was considerd sick and in need of help. People who were into stronger drugs like amphetamines and opiates, and did inject them could go special licensed doctors who would presribe them what they wanted, what amount etc. They could also get fresh needels.
Some doctors thoug would prescribe to much. Amphetamines esp to leak out and get in the hands of other, not before addicted. As we know now amphetamines in large doses will lead to insomnia. Not sleeping for a few days will lead to psychosis and other problems like anxiety and more.
The public and media learned about this and already in 2 years the whole thing were dropped and it became illegal. Nowother drugs like heroin, cannabis and more also started to be known in Sweden. Those were imeditely illegal as well.
So amphetamines get alot of the blame why Sweden have been overly strict on for example cannabis. Maybe Sweden overall is very naive and did not learn, even long into the game that you cant transfer the effects/sides of one drug to another.