I suspect that they commit suicide for the same reason that anyone does. As another commenter pointed out, the suicide rate among Foxconn workers is similar to

I suspect that they commit suicide for the same reason that anyone does. As another commenter pointed out, the suicide rate among Foxconn workers is similar to the rate for the Chinese populace in general, which probably tracks pretty well with the rate of depression. Not all seriously depressed people will commit suicide, but people who are depressed are more likely to commit suicide if they are under especially acute stress and don't have a good support system to help them deal with their current bout of stress and depression. Rural people who come to the big city to work in harsh conditions away from their families probably meet those two criteria especially well. They're overworked and lonely, and even though they're probably better fed, better paid, and maybe even better rested then they were home on the farm, psychologically they're under more pressure, and there really isn't anyone to keep an eye on them. So they have a day where the harsh conditions or pressures seem too much, and they jump off the building. And once the first person did it, people with a predisposition to suicide have that option hanging there in the back of their mind, and eventually do the same thing.