Can we reduce drug consumption by taxing it?

The initial argument that our stupid government made for increasing the tax on ready to drink drinks was that it would reduce binge drinking.

If that holds true, why not tax other substances where a reduction in consumption would be seen as a good thing.

For instance, we could tax the hell out of dope. Um, except that we can't, since it's illegal. But I am trying to be logical here - if a tax increase is such a good thing to do from a health perspective, why not legalise the stuff and then tax it to the rafters? Surely people would consume less of it once it is legal and taxed because, um, it attracts a high tax?

I just saying, some people's logic circuits need a rewire.