Happiness in intelligent people is the rarest thing I know.

Happiness in intelligent people is the rarest thing I know.
- Ernest Hemingway, author and journalist, Nobel laureate (1899-1961)

I came across this article, written about negative correlation between happiness and IQ.
http://www.scribd.com/doc/8778/Why-Intelligent-People-Tend-To-Be-Unhappy
Although I do realise that this may be true, I disagree with the general consensus that this lack of happiness is stimulated by social exclusion. I am considered naturally intelligent - not one of those ones who slave away, I am exceptionally socially active yet I too, am often unhappy. Below I have gathered the opinions of a diversity of people who have attempted to explain this confusing phenomena.

1) Are intelligent people less happy?
Intelligent people, I have found are typically less happy. The reason for this is simple; they are better able to rationalize their delusions. The ability to stomach truth has little to do with intelligence - nothing in fact. The intellect is far better at arguing away truths than at finding them. I'm not saying intelligent people are sad, I'm just saying it takes a lot more effort to prove happiness to them and they are greater at seeing the delusions of fake happiness hence their disposition of being less content.

2) Are intelligent people less happy?
Ignorance is bliss.

3) Are intelligent people less happy?
Maybe it's not intelligence that makes people happy or unhappy as it is perception. The different ways people perceive the world, themselves, and others are the determining factors in their happiness.

4) Are intelligent people less happy?
I would argue that (academically) intelligent people are not unhappy because they are able to "rationalize their delusions". They are likely unhappy because of the higher expectations for success placed on persons perceived to possess superior thinking skills. For example, consider a child who is a math prodigy at a very young age, but later, does not grow up to exceed the achievements of great mathematicians such as Einstein. The failure to live up to this very high and (perhaps unreasonable) expectation - something which persons of lesser mathematical ability would likely not entertain--might lead to unhappiness.

5) Are intelligent people less happy?
You need intelligence to find the truth and ignorance to believe in it - in the quest for the truth, the intelligent look perennially dissatisfied even while they are actually satisfying themselves at every step of uncovering and discovering the unending myths.

Personal Opinion;
In my opinion, happiness is dependent on the personality and surrounding environment - not directly on one's intelligence. However intelligence tends to influence the personality and surrounding environment hence having an indirect effect on the individual's happiness. I believe that intelligent people often see the realities that lie within this world. They are able to suss out ulterior motives, and possess the intuition to know and understand more than meets the eye. The truth is often ugly, and these intelligent individuals cannot help but see the truth at every corner. They say ignorance is bliss and it truly is. The more you know, the more you understand about this cruel world and the less happy you are prone to be. Unless, of course, you are one of those incredibly strong individuals who seek to solve each problem, and will continue to resolve the issues that surface. Unfortunately, where I'm from these types of individuals are not appreciated. Ignorance is key and stupidity is valued. Everybody's cool with the  'I don't care, because I don't understand.'