That is not quite easy... In Germany, we had very restrictive bans on drugs for a very long time and there were drastic punishments even for the smallest offences.
The effect was not that there was less drug consumption... On the contrary: the prices became higher and higher due to the illegality, and the crime rate increased.

Today, the legalisation of drugs is being debated, with good reason.

I think I should write about it in more detail... Thank you for the hint ;-))