That is awesome that you lived in Vientiane. I worked in Phnomh Penh for a year and I had always wanted to take an extended trip.
There isnt a lot of Opium use in tourist-filled areas, but to the majority of poor SE Asians, it is both the cheapest, most effective and most available medicines there are.
The worst part about SE Asia are the tourists. Kiwis and Aussies on spring break. They make a lot of noise and somehow end up dead, all the time, on what are known as lazy-rivers. Or, maybe one went down a natural, stone rock slide head first, breaks his neck and is legally dead before touching the water.
I was a tourist too though so I cant talk. I loved and appreciate greatly the culture of any foreign spot, but I didnt go to Cambodia purely because they needed it most, Iraq either. I wanted to help and I did help, but I also chose these places for the ready availability of Opiates.
I think people like myself ultimately and spring-breakers blur the line of what is and is not a true representation of that country.