Well, most European countries have similar laws like the United States. Possession and use of cannabis and other drugs is illegal. There are a few countries like Netherlands which have lax laws, and some countries have decriminalization laws (like Portugal).
There's a difference in policy with respect to sentencing. While in Finland (for example) possession of cannabis usually gets you a fine, it's possible to get a jail sentence for that in the United States (though it's legal to possess small amounts of cannabis in some states). However, this difference can be explained by tougher sentencing for crime in general
I don't understand where this idea comes from that drug laws are lax in Europe (maybe from pop culture references to the Netherlands?). They're pretty tough, but jail sentences are less common just as it's for other crimes.
No Western country I know of has an even remotely similar policy to the US on drugs. Most of them don't have >99% white population either btw.