When someone is excluded from a group, ousted or ostracized, it makes him or her unhappy. Loneliness and exclusion is the most common reason for anomie - losing the reason for life and will to live and to commit suicide.

And overtly high IQ is the most certain way to get excluded and ousted. The reason is the communication range. It makes you different and not fitting in.

The concept of communication range was established by Leta Hollingworth. It is +/- 2 standard deviations (roughly 30 points) up or down on one’s own IQ. It denotes the range where meaningful interaction (communication, discussion, conversation and socializing) is possible. If the IQ difference between two persons is more than 30 points, the communication breaks up. The higher IQ person will look like an incomprehensible nerd and the lower IQ as a moronic dullard - and they will not find anything common.

+/- 30 points does not sound much, but once the IQ is past 135, the downsides are imminent. When someone has a perfectly mediocre IQ (100 for Caucasian average), his communication range is from IQ 70 to IQ 130, which covers some 98% of the whole population. But when it is 135, it is from 105 to 165, which is approximately 36% of population. And it gets worse: if it is 162, your whole meaningful set of human interactions is restricted to Mensa qualifying people only (2% of whole population). Good luck for finding friends, acquaintances, colleagues - or spouse.

And it gets worse.

When the average IQ of a group is lower than the lower end of your communication range, the group will see you as a hostile outsider. They will do anything to bully you out of their presence. They will ostracize, excommunicate and oust you amongst themselves.

Source: Susanna Viljanen's answer to Are people with very high IQs generally happy? - Quora