One theory is Durkheim's suicide hypothesis: South Korea's industrial development has ripped apart the traditional society (already badly damaged by the country's partition and the Korean War), and social norms and society have not yet consolidated on new adaptive ways https://www.google.com/?gws_rd=ssl#q=durkheim+suicide+south+...

If so, we can hope that SK will gradually improve, especially if they can figure out how to corral the out-of-control signaling arms-race which is their educational system. (Although this also predicts bad news for China in the coming decades.)