Do intelligent people tend to be unhappy?

I have a lot of friends around who seems to be have a higher IQ than avarage people. But generally, including me, they find a lot of things to be sad. They are generally introverted and tend to be unhappy. Although they are successful at a lot of things like money, career, spouse…
A search about how intelligent people tend to be unhappy, enlightened me a lot. They say;

Children develop along four streams: intellectual, physical, emotional (psychological) and social. In classrooms, the smartest kids tend to be left out of more activities by other children than they are included in. They are “odd,” they are the geeks, they are social outsiders. In other words, they do not develop socially as well as they may develop intellectually or even physically where opportunities may exist for more progress.
Their emotional development, characterized by their ability to cope with risky or stressful situations, especially over long periods of time, also lags behind that of the average person.
Adults tend to believe that intelligent kids can deal with anything because they are intellectually superior. This inevitably includes situations where the intelligent kids have neither knowledge nor skills to support their experience. They go through the tough times alone. Adults don’t understand that they need help and other kids don’t want to associate with kids the social leaders say are outsiders.

It seems very logical to me. And this can explain why those friends of mine are so unhappy. So what about you, Are you unhappy and intelligent?