Well, with the draw-down of US forces, and the corresponding drying up of the money-wells that US forces bring during 'interventions,' Afghanistan's economy will move back into being dependent on the opium trade.
This is not a good sign for Russia or Europe, because falling prices always means greater availability. While there are a few people who can experiment with heroin and quit before they are hooked, the vast majority don't get off that easy.
Let's not forget that heroin use is not just a needle-jockey's game: a majority of users smoke it. The needle is an end-game strategy once tolerance has set in and the supply becomes harder to access because your too busy getting stoned to hold down a job. The needle offers more 'bang for the buck,' and so off you go to plunge down that death spiral.
With a drop in prices, there will be more heroin on the streets, which means more opportunity for experimentation.
In the early 1980s, when cocaine was starting to hit the streets, a lot of folks (like me) never experimented with it because it was fabulously expensive. Then Crack came to town, and instantly everyone was smoking and dying. I remember neighborhoods that were filled with 'crack zombies,' not unlike what you see now in rural towns fighting the meth epidemic.
Drugs are economy-driven in many ways. Addicts can't afford expensive habits.
When I quit smoking for the last time, it was not only because I hated being dependent, but I also could not afford it. I was paying for a couple of packs what once bought an entire carton for. In the US, smoking has gone down not only because it is difficult to find a place here you can smoke in public, but also because the prices are high and people can't grow tobacco in their own backyards.
Alcohol is harder to control because anyone with a plastic bag and some sugar is in business. Heck, they make it in prison...
Heroin is a different story. Its spread is largely driven by its transportability. This is bad news.