Singapore recently conducted a mental health survey, to measure the overall prevalence of psychiatric disorders. Some of the most common problems are depression, bipolar disorder, and alcoholism: no surprises there. All of these disorders occur at lower rates in Singapore than in the US, which is typical for Asian countries.
But the big surprise (and hilarious to me) was that Singapore has an extremely high level of people suffering from Obsessive-Compulsive Disorder (OCD): a lifetime prevalence rate of 3% (meaning 3% will develop it at some point in their lifetime). This doesn't sound that high, but when you compare it to the global rates of OCD, it is by far the highest in the world. Global rates are around 1-2%, and in the US it's a little over 2%.
Given what I've observed about Singaporean culture, this is not at all surprising. Since the causes of OCD are not clear (whether it's a genetic disorder, triggered by environmental stress, or something else), it's hard to say WHY so many Singaporeans have OCD. (I would guess that the intensely competitive environment children spend their formative years in has something to do with it.) But the high prevalence of people with OCD is very obvious, even in everyday life.