Yeah, I'm clearly no expert, but I believe that it's a free market for drug companies, as illustrated by the frequent television adverts for different products. I find them fascinating to watch- you'll hear the narrator going about how such and such a drug is the market-leading product for...
The level of addiction to opioid painkillers in the US is quite staggering compared to here. Much of that comes down to the way the health system operates I think. Here, you're registered with a GP, and if they prescribe you medication, any other doctor you go to will be able to see that, and...
I don't think the levels of use are any different to what they were in (say) the 1980s, it's just the drugs themselves that differ.
Heroin use hasn't changed a lot, nor, I suspect, has cocaine, MDMA (& derivatives) or cannabis use. Legal (and former legal) highs are another thing, however, and...