2001- my graduating class goes off into the world, half to college, maybe 1/4 to trade school, the rest go to join a family business or into an apprenticeship into a trade. A few go into the military. A few have no idea what to do and get low-level jobs wherever they can find them.
Pre-2008- The economy is booming, people who've gone to college are either 3 years post graduating, establishing themselves in their young careers, or just graduating from grad school, or for those that have entered a trade they've worked long enough to start having some standing in their chosen line of work.
2008-2010 economy explodes. Layoffs, bankruptcies, consolidations, offshoring. Immensely decreased consumer spending hits trades particularly hard- welders, mechanics, electricians, construction workers- all take massive hits to their profits. Business is scarce. People who've graduated from college and who are establishing their careers get laid off and have to move back into the county because that's where their safety net is- grandma and grandpa can take care of the kids while they hunt for work or work a low-paying job because that's all they can get. Military service men and women get done with their tour and come back to nothing- no job prospects, community college has closed, trade schools have closed, the factories where their fathers and mothers worked have all outsourced to 3rd world countries and closed.
In my rural county suddenly there's way more idle middle to late 20-somethings with no job and no prospects. No jobs to be found, no money to move. What I saw among the people I know/knew is that it only took a few people trying meth before it was like a powder keg going off- idle hands are the Devil's plathings, after all. People I went to high school with no hope for the future were doing meth because it was 3 minutes of bliss in stark contrast to the whirlpool of suck their lives had become. Grandma and grandpa were taking it because they couldn't afford painkillers. Teenagers were taking it because they were shithead teenagers and it was more accessible than pot. The "smarter" of the people I knew were cooking it because it was the only way they knew to make money. Once the door was open to meth then "fancier" stuff like painkillers started coming in and it was a way to feel like you were "better than" everyone else you knew who was doing meth. Oh yeah you were a drug addict, but at least your pills had a brand name. Enough meth labs blow up and the more enterprising of drug distributors can come in and sell addicts anything and everything they want, so if heroin is cheap enough that's what gets sold.
This article is written from a scholarly point of view and has a lot of conjecture but I definitely don't think they had any boots on the ground to make the conclusions that they did, particularly with regards to saying the epidemic in Appalachia is a result of on the job injuries. There are no jobs to get injured on anymore.
[Edit] I also absolutely agree with onetwotree's comment downthread, this is another ENORMOUS contributor to increased and sustained drug use in my tiny county: "Recovery is hard in tiny communities. All your friends are doing drugs, there are maybe 2 or 3 12-step meetings a week, no outpatient programs that you can attend while working, no sober living facilities, and treatment involves a trip to the big city." Also worth mentioning is that often those 12-step meetings are held in the basement of a church, which in my hometown means it's either your church which your whole family goes to and you grew up in (pretty damn hard to walk in there and admit to being an addict) or your friend's church that his whole family goes to and he grew up in- in both cases it's impossible to be anonymous.