I find most people in America that worked overtime felt that it was necessary to work because of all the tasks that needed to be completed. In Japan the overtime seems more "required" just to work overtime (not always the case of course). I think Americans get a lot more self-satisfaction when they finish their overtime shift (although they don't like it they know it was something that needed to be done).
I think there's a lot of stress and depression in the states from overwork (not as much depression from my group of friends), but not as much as Japan for a few reasons. One guess is that I find people in America more social than Japanese. Most of the "friends" relationships I see in Japan are more-so forced as they are coworkers who just go together and drink. I could be completely wrong here but I feel like they don't share their feelings and talk to reduce stress/depression as much as Americans.
One last thing about overtime is I feel most US companies have bursts of overtime when work needs to get done. Japanese companies often just have "permanent" overtime setting the mentality that they will be doing it forever.