I'm glad you brought up the point about mental health in the Christensen article, because when it opened with a discussion of Japan's life expectancy and mortality, my mind went first to Japanese healthcare and diet, and second to Japan's high suicide rate. East Asian countries are pretty notorious for the cutthroat environment surrounding salaried life, and I know this has negative effects of mental health. Apparently, the few studies that had been conducted on cognition and dementia in the U.S. had conflicting results, although one study found the prevalence of dementia in Japan had increased. For Japan, ADL was used as a measure of disability which decreased, but the examples given were practically all physical activities. Another thing to note is that, from what I've heard and read, contrary to the West in which mental health is becoming a topic of open discussion, insinuating that someone (much less oneself) has mental health issues in the East is still quite taboo.