The first real clues to understanding the disease were found in 1983 when a number of young addicts using contaminated heroin developed severe Parkinson's-like symptoms.
"A number of drug addicts in southern Indiana began shooting or injecting Opana, and we've learned by interviewing some of these people that they injected methamphetamine too.
And as any number of addicts will tell you, it is easy to lose yourself to the narcotic effects of flats fishing.
In Lazarevac, a Serbian city containing a high number of addicts, we meet Zlatan*, a former police commissioner who is talking to us anonymously, fearing a threat to his life.
Heroin addiction is increasingly treated as an illness rather than a crime: clean needles are available in many rich countries, and a few, including Britain and Switzerland, even prescribe heroin to a small number of addicts.
But he and Bubela agree that such increased access would inevitably result in a greater number of addicts.
The pills go to a growing number of addicts in the Philippines and Thailand, as well as in Arab countries, where traditional amphetamines also remain popular.Government attempts to crack down on one new drug after another bring to mind a game of whack-a-mole, says one expert.
Although the two reported cases are believed to have been related, there are fears that the fact it has already spread as far as Arizona may suggest the US is likely see a large number of addicts over the coming years.
Many people were understandably terrified; they believed a huge number of addicts were about to head home when the war ended.
It might have fallen out of favor with the younger generation of drug users, for whom the 1990s was enough warning of the drug's many downsides, but a large number of addicts who started using in the 1970s and 80s are still around.
